diff --git a/bin/clear-all-heartbeats.py b/bin/clear-all-heartbeats.py
index 28db7fbb7..628228f97 100755
--- a/bin/clear-all-heartbeats.py
+++ b/bin/clear-all-heartbeats.py
@@ -43,7 +43,7 @@ def main(host, port, database):
         count += 1
 
     batch_client.execute()
-    print("{} heartbeats deleted!".format(count))
+    print(f"{count} heartbeats deleted!")
     exit(0)
 
 
diff --git a/bin/clear-heartbeat-status.py b/bin/clear-heartbeat-status.py
index f583bfcfc..f1a0fce7c 100755
--- a/bin/clear-heartbeat-status.py
+++ b/bin/clear-heartbeat-status.py
@@ -25,7 +25,7 @@ def main(host, port, account_id, folder_id, device_id):
 
     print("Clearing heartbeat status...")
     n = clear_heartbeat_status(account_id, folder_id, device_id, host, port)
-    print("{} folders cleared.".format(n))
+    print(f"{n} folders cleared.")
     exit(0)
 
 
diff --git a/bin/contact-search-backfill.py b/bin/contact-search-backfill.py
index 999f23dc1..ecfb8b956 100755
--- a/bin/contact-search-backfill.py
+++ b/bin/contact-search-backfill.py
@@ -23,7 +23,7 @@ def main(namespace_ids):
     maybe_enable_rollbar()
 
     for namespace_id in namespace_ids:
-        log.info("indexing namespace {namespace_id}".format(namespace_id=namespace_id))
+        log.info(f"indexing namespace {namespace_id}")
         index_namespace(namespace_id)
 
 
diff --git a/bin/contact-search-service.py b/bin/contact-search-service.py
index aeafdd8b0..a498ebc4c 100755
--- a/bin/contact-search-service.py
+++ b/bin/contact-search-service.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-""" Start the contact search indexing service. """
+"""Start the contact search indexing service."""
 from gevent import monkey
 
 monkey.patch_all()
diff --git a/bin/correct-autoincrements.py b/bin/correct-autoincrements.py
index cd24fe5bf..017c2f3c7 100755
--- a/bin/correct-autoincrements.py
+++ b/bin/correct-autoincrements.py
@@ -28,14 +28,14 @@ def reset_db(dry_run):
             engine = engine_manager.engines[key]
             schema = shard["SCHEMA_NAME"]
 
-            print("Resetting invalid autoincrements for database: {}".format(schema))
+            print(f"Resetting invalid autoincrements for database: {schema}")
             reset_tables = reset_invalid_autoincrements(engine, schema, key, dry_run)
             if dry_run:
                 print("dry_run=True")
             if reset_tables:
                 print("Reset tables: {}".format(", ".join(reset_tables)))
             else:
-                print("Schema {} okay".format(schema))
+                print(f"Schema {schema} okay")
 
 
 if __name__ == "__main__":
diff --git a/bin/create-db.py b/bin/create-db.py
index 0b8146c2d..5772920c0 100755
--- a/bin/create-db.py
+++ b/bin/create-db.py
@@ -53,12 +53,12 @@ def main(target_hostname, host_ip):
             )
 
             schema_name = shard["SCHEMA_NAME"]
-            print("Setting up database: {}".format(schema_name))
+            print(f"Setting up database: {schema_name}")
 
             # Create the database IF needed.
             base_engine.execute(
-                "CREATE DATABASE IF NOT EXISTS {} DEFAULT CHARACTER "
-                "SET utf8mb4 DEFAULT COLLATE utf8mb4_general_ci;".format(schema_name)
+                f"CREATE DATABASE IF NOT EXISTS {schema_name} DEFAULT CHARACTER "
+                "SET utf8mb4 DEFAULT COLLATE utf8mb4_general_ci;"
             )
 
             engine = engine_manager.engines[int(key)]
@@ -71,9 +71,7 @@ def main(target_hostname, host_ip):
                 assert (
                     current_revision
                 ), "Need current revision in alembic_version table."
-                print(
-                    "Already revisioned by alembic version: {}".format(current_revision)
-                )
+                print(f"Already revisioned by alembic version: {current_revision}")
             else:
                 # Initialize shards, stamp alembic revision
                 print("Initializing database.")
@@ -81,7 +79,7 @@ def main(target_hostname, host_ip):
                 alembic_ini_filename = os.environ.get("ALEMBIC_INI_PATH", "alembic.ini")
                 assert os.path.isfile(
                     alembic_ini_filename
-                ), "Must have alembic.ini file at {}".format(alembic_ini_filename)
+                ), f"Must have alembic.ini file at {alembic_ini_filename}"
                 alembic_cfg = alembic.config.Config(alembic_ini_filename)
                 # Alembic option values need to be strings.
                 alembic_cfg.set_main_option("shard_id", str(key))
diff --git a/bin/create-encryption-keys.py b/bin/create-encryption-keys.py
index 5936b68ad..1f322484f 100755
--- a/bin/create-encryption-keys.py
+++ b/bin/create-encryption-keys.py
@@ -18,8 +18,7 @@ def main():
     # If the config contains encryption keys, don't override.
     if config.get("SECRET_ENCRYPTION_KEY"):
         raise Exception(
-            "Encryption keys already present in secrets config "
-            "file {0}".format(secrets_path)
+            "Encryption keys already present in secrets config " f"file {secrets_path}"
         )
 
     # Generate keys
@@ -37,12 +36,10 @@ def main():
     # Update it
     try:
         with open(secrets_path, "a") as f:
-            print("Writing keys to secrets config file {0}".format(secrets_path))
+            print(f"Writing keys to secrets config file {secrets_path}")
             yaml.dump(data, f, default_flow_style=False)
-    except IOError:
-        raise Exception(
-            "Check file write permissions on config file {0}".format(secrets_path)
-        )
+    except OSError:
+        raise Exception(f"Check file write permissions on config file {secrets_path}")
 
     # Update the config dict
     config.update(data)
diff --git a/bin/delete-account-data.py b/bin/delete-account-data.py
index 271f88ff8..3bbfb4c16 100755
--- a/bin/delete-account-data.py
+++ b/bin/delete-account-data.py
@@ -42,16 +42,16 @@ def delete_account_data(account_id, dry_run, yes, throttle):
         account = db_session.query(Account).get(account_id)
 
         if not account:
-            print("Account with id {} does NOT exist.".format(account_id))
-            return
+            print(f"Account with id {account_id} does NOT exist.")
+            return None
 
         email_address = account.email_address
         namespace_id = account.namespace.id
 
         if account.sync_should_run or not account.is_marked_for_deletion:
             print(
-                "Account with id {} NOT marked for deletion.\n"
-                "Will NOT delete, goodbye.".format(account_id)
+                f"Account with id {account_id} NOT marked for deletion.\n"
+                "Will NOT delete, goodbye."
             )
             return -1
 
@@ -69,7 +69,7 @@ def delete_account_data(account_id, dry_run, yes, throttle):
             print("Will NOT delete, goodbye.")
             return 0
 
-    print("Deleting account with id: {}...".format(account_id))
+    print(f"Deleting account with id: {account_id}...")
     start = time.time()
 
     # Delete data in database
@@ -77,18 +77,18 @@ def delete_account_data(account_id, dry_run, yes, throttle):
         print("Deleting database data")
         delete_namespace(namespace_id, dry_run=dry_run, throttle=throttle)
     except Exception as e:
-        print("Database data deletion failed! Error: {}".format(str(e)))
+        print(f"Database data deletion failed! Error: {str(e)}")
         return -1
 
     database_end = time.time()
-    print("Database data deleted. Time taken: {}".format(database_end - start))
+    print(f"Database data deleted. Time taken: {database_end - start}")
 
     # Delete liveness data
     print("Deleting liveness data")
     clear_heartbeat_status(account_id)
 
     end = time.time()
-    print("All data deleted successfully! TOTAL time taken: {}".format(end - start))
+    print(f"All data deleted successfully! TOTAL time taken: {end - start}")
     return 0
 
 
diff --git a/bin/get-accounts-for-host.py b/bin/get-accounts-for-host.py
index 11fcc2b91..c67d7d851 100644
--- a/bin/get-accounts-for-host.py
+++ b/bin/get-accounts-for-host.py
@@ -16,7 +16,7 @@ def main(hostname):
     with global_session_scope() as db_session:
         account_ids = db_session.query(Account.id).filter(Account.sync_host == hostname)
 
-        print("Accounts being synced by {}:".format(hostname))
+        print(f"Accounts being synced by {hostname}:")
         for account_id in account_ids:
             print(account_id[0])
         db_session.commit()
diff --git a/bin/get-id.py b/bin/get-id.py
index c2b3c96dd..61926153b 100755
--- a/bin/get-id.py
+++ b/bin/get-id.py
@@ -43,7 +43,7 @@ def main(type, id, public_id):
     type = type.lower()
 
     if type not in cls_for_type:
-        print("Error: unknown type '{}'".format(type))
+        print(f"Error: unknown type '{type}'")
         sys.exit(-1)
 
     cls = cls_for_type[type]
diff --git a/bin/get-object.py b/bin/get-object.py
index 948e95917..27cba0fa4 100755
--- a/bin/get-object.py
+++ b/bin/get-object.py
@@ -58,7 +58,7 @@ def main(type, id, public_id, account_id, namespace_id, readwrite):
     type = type.lower()
 
     if type not in cls_for_type:
-        print("Error: unknown type '{}'".format(type))
+        print(f"Error: unknown type '{type}'")
         sys.exit(-1)
 
     cls = cls_for_type[type]
diff --git a/bin/inbox-auth.py b/bin/inbox-auth.py
index 6c1ad4f90..631c959c4 100755
--- a/bin/inbox-auth.py
+++ b/bin/inbox-auth.py
@@ -78,7 +78,7 @@ def main(email_address, reauth, target, provider):
         except NotSupportedError as e:
             sys.exit(str(e))
 
-    print("OK. Authenticated account for {}".format(email_address))
+    print(f"OK. Authenticated account for {email_address}")
 
 
 if __name__ == "__main__":
diff --git a/bin/inbox-start.py b/bin/inbox-start.py
index f34fb7027..69638a12f 100755
--- a/bin/inbox-start.py
+++ b/bin/inbox-start.py
@@ -39,7 +39,7 @@
 
 esc = "\033"
 
-banner = r"""{esc}[1;95m
+banner = rf"""{esc}[1;95m
       _   _       _
      | \ | |     | |
      |  \| |_   _| | __ _ ___
@@ -53,9 +53,7 @@
 
      {esc}[0m
      Use CTRL-C to stop.
-    """.format(
-    esc=esc
-)
+    """
 
 
 @click.command()
@@ -110,7 +108,7 @@ def main(prod, enable_tracer, enable_profiler, config, process_num, exit_after):
 
     total_processes = int(os.environ.get("MAILSYNC_PROCESSES", 1))
 
-    setproctitle.setproctitle("sync-engine-{}".format(process_num))
+    setproctitle.setproctitle(f"sync-engine-{process_num}")
 
     log = get_logger()
     log.info(
@@ -132,7 +130,7 @@ def main(prod, enable_tracer, enable_profiler, config, process_num, exit_after):
     port = 16384 + process_num
     enable_profiler_api = inbox_config.get("DEBUG_PROFILING_ON")
 
-    process_identifier = "{}:{}".format(platform.node(), process_num)
+    process_identifier = f"{platform.node()}:{process_num}"
 
     if exit_after:
         exit_after = exit_after.split(":")
diff --git a/bin/migrate-db.py b/bin/migrate-db.py
index 1d580c4c1..1315b658f 100755
--- a/bin/migrate-db.py
+++ b/bin/migrate-db.py
@@ -17,7 +17,7 @@ def main():
     alembic_ini_filename = os.environ.get("ALEMBIC_INI_PATH", "alembic.ini")
     assert os.path.isfile(
         alembic_ini_filename
-    ), "Missing alembic.ini file at {}".format(alembic_ini_filename)
+    ), f"Missing alembic.ini file at {alembic_ini_filename}"
 
     database_hosts = config.get_required("DATABASE_HOSTS")
 
@@ -33,15 +33,13 @@ def main():
             key = shard["ID"]
 
             try:
-                print("Upgrading shard_id {}".format(key))
+                print(f"Upgrading shard_id {key}")
                 alembic_cfg = alembic.config.Config(alembic_ini_filename)
                 alembic_cfg.set_main_option("shard_id", str(key))
                 alembic.command.upgrade(alembic_cfg, "head")
-                print("Upgraded shard_id {}\n".format(key))
+                print(f"Upgraded shard_id {key}\n")
             except alembic.util.CommandError as e:
-                print(
-                    "FAILED to upgrade shard_id {} with error: {}".format(key, str(e))
-                )
+                print(f"FAILED to upgrade shard_id {key} with error: {str(e)}")
                 continue
 
 
diff --git a/bin/mysql-prompt.py b/bin/mysql-prompt.py
index 1bd68bcb4..1bdc68bf7 100755
--- a/bin/mysql-prompt.py
+++ b/bin/mysql-prompt.py
@@ -40,7 +40,7 @@ def main(shard_num):
 
     for key in creds.keys():
         if creds[key] is None:
-            print("Error: {key} is None".format(key=key))
+            print(f"Error: {key} is None")
             sys.exit(-1)
 
     proc = subprocess.Popen(
diff --git a/bin/set-desired-host.py b/bin/set-desired-host.py
index b22ee6614..9ddef56eb 100644
--- a/bin/set-desired-host.py
+++ b/bin/set-desired-host.py
@@ -19,9 +19,9 @@ def main(account_id, desired_host, dry_run, toggle_sync):
     with global_session_scope() as db_session:
         account = db_session.query(Account).get(int(account_id))
 
-        print("Before sync host: {}".format(account.sync_host))
-        print("Before desired sync host: {}".format(account.desired_sync_host))
-        print("Before sync should run: {}".format(account.sync_should_run))
+        print(f"Before sync host: {account.sync_host}")
+        print(f"Before desired sync host: {account.desired_sync_host}")
+        print(f"Before sync should run: {account.sync_should_run}")
 
         if dry_run:
             return
@@ -29,9 +29,9 @@ def main(account_id, desired_host, dry_run, toggle_sync):
         if toggle_sync:
             account.sync_should_run = not account.sync_should_run
 
-        print("After sync host: {}".format(account.sync_host))
-        print("After desired sync host: {}".format(account.desired_sync_host))
-        print("After sync should run: {}".format(account.sync_should_run))
+        print(f"After sync host: {account.sync_host}")
+        print(f"After desired sync host: {account.desired_sync_host}")
+        print(f"After sync should run: {account.sync_should_run}")
         db_session.commit()
 
 
diff --git a/bin/stamp-db.py b/bin/stamp-db.py
index 4dca8dcd4..b846ae932 100755
--- a/bin/stamp-db.py
+++ b/bin/stamp-db.py
@@ -18,7 +18,7 @@ def main(revision_id):
     alembic_ini_filename = os.environ.get("ALEMBIC_INI_PATH", "alembic.ini")
     assert os.path.isfile(
         alembic_ini_filename
-    ), "Missing alembic.ini file at {}".format(alembic_ini_filename)
+    ), f"Missing alembic.ini file at {alembic_ini_filename}"
 
     database_hosts = config.get_required("DATABASE_HOSTS")
 
@@ -34,13 +34,13 @@ def main(revision_id):
             key = shard["ID"]
 
             try:
-                print("Stamping shard_id {}".format(key))
+                print(f"Stamping shard_id {key}")
                 alembic_cfg = alembic.config.Config(alembic_ini_filename)
                 alembic_cfg.set_main_option("shard_id", str(key))
                 alembic.command.stamp(alembic_cfg, revision_id)
-                print("Stamped shard_id {}\n".format(key))
+                print(f"Stamped shard_id {key}\n")
             except alembic.util.CommandError as e:
-                print("FAILED to stamp shard_id {} with error: {}".format(key, str(e)))
+                print(f"FAILED to stamp shard_id {key} with error: {str(e)}")
                 continue
 
 
diff --git a/bin/syncback-service.py b/bin/syncback-service.py
index 3d0a8fec2..a65648d4a 100755
--- a/bin/syncback-service.py
+++ b/bin/syncback-service.py
@@ -58,7 +58,7 @@
 )
 def main(prod, config, process_num, syncback_id, enable_tracer, enable_profiler):
     """Launch the actions syncback service."""
-    setproctitle("syncback-{}".format(process_num))
+    setproctitle(f"syncback-{process_num}")
 
     maybe_enable_rollbar()
 
diff --git a/bin/syncback-stats.py b/bin/syncback-stats.py
index 23fb36663..825b8b6f5 100755
--- a/bin/syncback-stats.py
+++ b/bin/syncback-stats.py
@@ -40,16 +40,10 @@ def main():
                 .group_by(ActionLog.namespace_id)
             ):
                 print(
-                    "{} (pending actions), {} (shard), {} (namespace)".format(
-                        c, key, namespace_id
-                    )
+                    f"{c} (pending actions), {key} (shard), {namespace_id} (namespace)"
                 )
                 total_pending_actions += c
-            print(
-                "total pending actions for shard {}: {}".format(
-                    key, total_pending_actions
-                )
-            )
+            print(f"total pending actions for shard {key}: {total_pending_actions}")
 
 
 if __name__ == "__main__":
diff --git a/bin/unschedule-account-syncs.py b/bin/unschedule-account-syncs.py
index cf12018d6..8a8e3b047 100755
--- a/bin/unschedule-account-syncs.py
+++ b/bin/unschedule-account-syncs.py
@@ -46,7 +46,7 @@ def main(dry_run, number, hostname, process):
         if process is not None:
             hostname = ":".join([hostname, process])
         to_unschedule = db_session.query(Account.id).filter(
-            Account.sync_host.like("{}%".format(hostname))
+            Account.sync_host.like(f"{hostname}%")
         )
         if number:
             to_unschedule = to_unschedule.limit(number)
diff --git a/bin/update-categories.py b/bin/update-categories.py
index 3ed4b3c8d..4e27cc2e6 100755
--- a/bin/update-categories.py
+++ b/bin/update-categories.py
@@ -22,14 +22,14 @@ def main(shard_id):
 
 
 def update_categories_for_shard(shard_id):
-    print("Updating categories for shard {}".format(shard_id))
+    print(f"Updating categories for shard {shard_id}")
 
     engine = engine_manager.engines[shard_id]
 
     query = "UPDATE category SET name='' WHERE name is NULL;"
     engine.execute(query)
 
-    print("Updated names, updating deleted_at for shard {}".format(shard_id))
+    print(f"Updated names, updating deleted_at for shard {shard_id}")
 
     query = (
         "UPDATE category SET deleted_at='1970-01-01 00:00:00' WHERE deleted_at is NULL;"
@@ -38,14 +38,14 @@ def update_categories_for_shard(shard_id):
 
 
 def update_folders_and_labels_for_shard(shard_id):
-    print("Updating folders for shard {}".format(shard_id))
+    print(f"Updating folders for shard {shard_id}")
 
     engine = engine_manager.engines[shard_id]
 
     query = "UPDATE folder SET canonical_name='' WHERE canonical_name is NULL;"
     engine.execute(query)
 
-    print("Updated folders, updating labels for shard {}".format(shard_id))
+    print(f"Updated folders, updating labels for shard {shard_id}")
 
     query = "UPDATE label SET canonical_name='' WHERE canonical_name is NULL;"
     engine.execute(query)
diff --git a/bin/verify-db.py b/bin/verify-db.py
index b2ccc1627..e21d40046 100755
--- a/bin/verify-db.py
+++ b/bin/verify-db.py
@@ -24,7 +24,7 @@ def main():
             engine = engine_manager.engines[key]
             schema = shard["SCHEMA_NAME"]
 
-            print("Verifying database: {}".format(schema))
+            print(f"Verifying database: {schema}")
             verify_db(engine, schema, key)
 
 
diff --git a/inbox/actions/backends/generic.py b/inbox/actions/backends/generic.py
index 16857a6c5..381e48f3b 100644
--- a/inbox/actions/backends/generic.py
+++ b/inbox/actions/backends/generic.py
@@ -1,5 +1,5 @@
-""" Operations for syncing back local datastore changes to
-    generic IMAP providers.
+"""Operations for syncing back local datastore changes to
+generic IMAP providers.
 """
 import contextlib
 from collections import defaultdict
diff --git a/inbox/actions/backends/gmail.py b/inbox/actions/backends/gmail.py
index b4514ddaf..80bf01d8f 100644
--- a/inbox/actions/backends/gmail.py
+++ b/inbox/actions/backends/gmail.py
@@ -1,4 +1,4 @@
-""" Operations for syncing back local datastore changes to Gmail. """
+"""Operations for syncing back local datastore changes to Gmail."""
 
 import contextlib
 from imaplib import IMAP4
diff --git a/inbox/actions/base.py b/inbox/actions/base.py
index 7320f1e8d..de0208b54 100644
--- a/inbox/actions/base.py
+++ b/inbox/actions/base.py
@@ -1,4 +1,4 @@
-""" Code for propagating Nylas datastore changes to account backends.
+"""Code for propagating Nylas datastore changes to account backends.
 
 Syncback actions don't update anything in the local datastore; the Nylas
 datastore is updated asynchronously (see namespace.py) and bookkeeping about
diff --git a/inbox/api/err.py b/inbox/api/err.py
index 482ac348e..a6a4fd178 100644
--- a/inbox/api/err.py
+++ b/inbox/api/err.py
@@ -51,7 +51,8 @@ class APIException(Exception):
 
 class InputError(APIException):
     """Raised on invalid user input (missing required parameter, value too
-    long, etc.)"""
+    long, etc.)
+    """
 
     status_code = 400
 
diff --git a/inbox/api/kellogs.py b/inbox/api/kellogs.py
index 6e92aa340..5a6af5232 100644
--- a/inbox/api/kellogs.py
+++ b/inbox/api/kellogs.py
@@ -120,7 +120,8 @@ def _get_namespace_public_id(obj):
     def _format_participant_data(participant):
         """Event.participants is a JSON blob which may contain internal data.
         This function returns a dict with only the data we want to make
-        public."""
+        public.
+        """
         dct = {}
         for attribute in ["name", "status", "email", "comment"]:
             dct[attribute] = participant.get(attribute)
diff --git a/inbox/api/ns_api.py b/inbox/api/ns_api.py
index 44c6b59c5..c49724d78 100644
--- a/inbox/api/ns_api.py
+++ b/inbox/api/ns_api.py
@@ -631,9 +631,7 @@ def message_read_api(public_id):
         else:
             # Try getting the message from the email provider.
             account = g.namespace.account
-            statsd_string = "api.direct_fetching.{}.{}".format(
-                account.provider, account.id
-            )
+            statsd_string = f"api.direct_fetching.{account.provider}.{account.id}"
 
             try:
                 with statsd_client.timer(f"{statsd_string}.provider_latency"):
@@ -685,8 +683,8 @@ def message_read_api(public_id):
 
             request.environ["log_context"]["message_id"] = message.id
             raise NotFoundError(
-                "Couldn't find raw contents for message `{}`. "
-                "Please try again in a few minutes.".format(public_id)
+                f"Couldn't find raw contents for message `{public_id}`. "
+                "Please try again in a few minutes."
             )
 
     return encoder.jsonify(message)
@@ -926,9 +924,7 @@ def folder_label_delete_api(public_id):
         messages_exist = g.db_session.query(messages_with_category).scalar()
         if messages_exist:
             raise InputError(
-                "Folder {} cannot be deleted because it contains messages.".format(
-                    public_id
-                )
+                f"Folder {public_id} cannot be deleted because it contains messages."
             )
 
         if g.api_features.optimistic_updates:
@@ -1855,7 +1851,8 @@ def multi_send(draft_id):
     session. Sends a copy of the draft at draft_id to the specified address
     with the specified body, and ensures that a corresponding sent message is
     either not created in the user's Sent folder or is immediately
-    deleted from it."""
+    deleted from it.
+    """
     request_started = time.time()
     account = g.namespace.account
 
@@ -1898,8 +1895,8 @@ def multi_send(draft_id):
 @app.route("/send-multiple/<draft_id>", methods=["DELETE"])
 def multi_send_finish(draft_id):
     """Closes out a multi-send session by marking the sending draft as sent
-    and moving it to the user's Sent folder."""
-
+    and moving it to the user's Sent folder.
+    """
     account = g.namespace.account
 
     if account.discriminator == "easaccount":
diff --git a/inbox/api/srv.py b/inbox/api/srv.py
index bbeac0191..e06767313 100644
--- a/inbox/api/srv.py
+++ b/inbox/api/srv.py
@@ -70,13 +70,13 @@ def auth():
         or request.path.startswith("/w/")
         or request.path.startswith("/metrics")
     ):
-        return
+        return None
 
     if not request.authorization or not request.authorization.username:
         AUTH_ERROR_MSG = (
             "Could not verify access credential.",
             401,
-            {"WWW-Authenticate": 'Basic realm="API ' 'Access Token Required"'},
+            {"WWW-Authenticate": 'Basic realm="API Access Token Required"'},
         )
 
         auth_header = request.headers.get("Authorization", None)
@@ -108,7 +108,7 @@ def auth():
                 (
                     "Could not verify access credential.",
                     401,
-                    {"WWW-Authenticate": 'Basic realm="API ' 'Access Token Required"'},
+                    {"WWW-Authenticate": 'Basic realm="API Access Token Required"'},
                 )
             )
 
@@ -275,7 +275,6 @@ def modify_account(namespace_public_id):
 
     This stops syncing an account until it is explicitly resumed.
     """
-
     data = request.get_json(force=True)
 
     with global_session_scope() as db_session:
@@ -335,7 +334,8 @@ def home():
 @app.route("/logout")
 def logout():
     """Utility function used to force browsers to reset cached HTTP Basic Auth
-    credentials"""
+    credentials
+    """
     return make_response(
         (
             "<meta http-equiv='refresh' content='0; url=/''>.",
diff --git a/inbox/api/update.py b/inbox/api/update.py
index 0aa0e72ef..4bfdcfb9c 100644
--- a/inbox/api/update.py
+++ b/inbox/api/update.py
@@ -109,7 +109,7 @@ def update_message_flags(message, db_session, optimistic, unread=None, starred=N
 def parse_folder(request_data, db_session, namespace_id):
     # TODO deprecate being able to post "folder" and not "folder_id"
     if "folder_id" not in request_data and "folder" not in request_data:
-        return
+        return None
     folder_public_id = request_data.pop("folder_id", None) or request_data.pop(
         "folder", None
     )
@@ -153,7 +153,7 @@ def update_message_folder(message, db_session, category, optimistic):
 def parse_labels(request_data, db_session, namespace_id):
     # TODO deprecate being able to post "labels" and not "label_ids"
     if "label_ids" not in request_data and "labels" not in request_data:
-        return
+        return None
 
     label_public_ids = request_data.pop("label_ids", []) or request_data.pop(
         "labels", []
diff --git a/inbox/api/wsgi.py b/inbox/api/wsgi.py
index 9920c8788..9167e752e 100644
--- a/inbox/api/wsgi.py
+++ b/inbox/api/wsgi.py
@@ -18,7 +18,8 @@
 
 class NylasWSGIHandler(WSGIHandler):
     """Custom WSGI handler class to customize request logging. Based on
-    gunicorn.workers.ggevent.PyWSGIHandler."""
+    gunicorn.workers.ggevent.PyWSGIHandler.
+    """
 
     def log_request(self):
         # gevent.pywsgi tries to call log.write(), but Python logger objects
@@ -94,7 +95,8 @@ def handle_error(self, type, value, tb):
 
 class NylasWSGIWorker(GeventWorker):
     """Custom worker class for gunicorn. Based on
-    gunicorn.workers.ggevent.GeventPyWSGIWorker."""
+    gunicorn.workers.ggevent.GeventPyWSGIWorker.
+    """
 
     server_class = WSGIServer
     wsgi_handler = NylasWSGIHandler
diff --git a/inbox/auth/oauth.py b/inbox/auth/oauth.py
index 7efdd9389..8fc0d2269 100644
--- a/inbox/auth/oauth.py
+++ b/inbox/auth/oauth.py
@@ -133,7 +133,7 @@ def _new_access_token_from_authalligator(
                 )
                 aa_account = aa_response
             except AccountError as exc:
-                log.warn(
+                log.warning(
                     "AccountError during AuthAlligator account query",
                     account_id=account.id,
                     error_code=exc.code and exc.code.value,
diff --git a/inbox/contacts/algorithms.py b/inbox/contacts/algorithms.py
index 56f408470..4341ec68b 100644
--- a/inbox/contacts/algorithms.py
+++ b/inbox/contacts/algorithms.py
@@ -186,7 +186,7 @@ def _combine_similar_molecules(molecules_list):
         combined = [False] * len(molecules_list)
         new_guys = []
         for j in range(new_guys_start_idx, len(molecules_list)):
-            for i in range(0, j):
+            for i in range(j):
                 if combined[i]:
                     continue
                 (g1, m1), (g2, m2) = molecules_list[i], molecules_list[j]
diff --git a/inbox/contacts/carddav.py b/inbox/contacts/carddav.py
index bcee51f83..508007a30 100644
--- a/inbox/contacts/carddav.py
+++ b/inbox/contacts/carddav.py
@@ -52,7 +52,6 @@ def __init__(self, email_address, password, base_url):
 
     def get_principal_url(self):
         """Use PROPFIND method to find the `principal` carddav url"""
-
         payload = """
             <A:propfind xmlns:A='DAV:'>
                 <A:prop>
diff --git a/inbox/contacts/crud.py b/inbox/contacts/crud.py
index 9947116e0..03741fbbb 100644
--- a/inbox/contacts/crud.py
+++ b/inbox/contacts/crud.py
@@ -1,5 +1,6 @@
 """Utility functions for creating, reading, updating and deleting contacts.
-Called by the API."""
+Called by the API.
+"""
 import uuid
 
 from inbox.models import Contact
diff --git a/inbox/contacts/icloud.py b/inbox/contacts/icloud.py
index 163c82820..86375ea08 100644
--- a/inbox/contacts/icloud.py
+++ b/inbox/contacts/icloud.py
@@ -105,7 +105,7 @@ def get_items(self, sync_from_dt=None, max_results=100000):
                 # TODO add paging for requesting all
                 self.log.error(
                     "Error parsing CardDav response into contact: "
-                    "{}".format(ET.tostring(refprop))
+                    f"{ET.tostring(refprop)}"
                 )
                 continue
 
diff --git a/inbox/contacts/processing.py b/inbox/contacts/processing.py
index a1088a5f8..184b69d9f 100644
--- a/inbox/contacts/processing.py
+++ b/inbox/contacts/processing.py
@@ -43,7 +43,7 @@ def _get_contact_map(db_session, namespace_id, all_addresses):
 
 def _get_contact_from_map(contact_map, name, email_address):
     if not valid_email(email_address):
-        return
+        return None
 
     canonicalized_address = canonicalize(email_address)
     contact = contact_map.get(canonicalized_address)
diff --git a/inbox/contacts/search.py b/inbox/contacts/search.py
index c4f87b980..076ccda1f 100644
--- a/inbox/contacts/search.py
+++ b/inbox/contacts/search.py
@@ -93,8 +93,8 @@ def __init__(self, namespace_id):
 
     def _fetch_search_page(self, **kwargs):
         """Make sure we always filter results by namespace and apply the
-        correct query options."""
-
+        correct query options.
+        """
         namespace_filter = f"(and namespace_id:{self.namespace_id})"
         if "query" not in kwargs:
             kwargs["query"] = namespace_filter
diff --git a/inbox/contacts/vcard.py b/inbox/contacts/vcard.py
index fc8d37432..72d12b101 100644
--- a/inbox/contacts/vcard.py
+++ b/inbox/contacts/vcard.py
@@ -35,13 +35,12 @@
 
 
 def list_clean(string):
-    """transforms a comma seperated string to a list, stripping whitespaces
+    """Transforms a comma seperated string to a list, stripping whitespaces
     "HOME, WORK,pref" -> ['HOME', 'WORK', 'pref']
 
     string: string of comma seperated elements
     returns: list()
     """
-
     string = string.split(",")
     rstring = list()
     for element in string:
@@ -144,7 +143,7 @@ def get_names(display_name):
 
 
 def fix_vobject(vcard):
-    """trying to fix some more or less common errors in vcards
+    """Trying to fix some more or less common errors in vcards
 
     for now only missing FN properties are handled (and reconstructed from N)
     :type vcard: vobject.base.Component (vobject based vcard)
@@ -270,7 +269,7 @@ def alt_keys(self):
         return keylist
 
     def print_email(self):
-        """prints only name, email and type for use with mutt"""
+        """Prints only name, email and type for use with mutt"""
         collector = list()
         try:
             for one in self["EMAIL"]:
@@ -284,7 +283,7 @@ def print_email(self):
             return ""
 
     def print_tel(self):
-        """prints only name, email and type for use with mutt"""
+        """Prints only name, email and type for use with mutt"""
         collector = list()
         try:
             for one in self["TEL"]:
@@ -332,16 +331,18 @@ def _line_helper(self, line):
 
     @property
     def vcf(self):
-        """serialize to VCARD as specified in RFC2426,
+        """Serialize to VCARD as specified in RFC2426,
         if no UID is specified yet, one will be added (as a UID is mandatory
         for carddav as specified in RFC6352
-        TODO make shure this random uid is unique"""
+        TODO make shure this random uid is unique
+        """
         import random
         import string
 
         def generate_random_uid():
-            """generate a random uid, when random isn't broken, getting a
-            random UID from a pool of roughly 10^56 should be good enough"""
+            """Generate a random uid, when random isn't broken, getting a
+            random UID from a pool of roughly 10^56 should be good enough
+            """
             choice = string.ascii_uppercase + string.digits
             return "".join([random.choice(choice) for _ in range(36)])
 
diff --git a/inbox/crispin.py b/inbox/crispin.py
index d2572de2a..6ebd92bf2 100644
--- a/inbox/crispin.py
+++ b/inbox/crispin.py
@@ -1,4 +1,4 @@
-""" IMAPClient wrapper for the Nylas Sync Engine."""
+"""IMAPClient wrapper for the Nylas Sync Engine."""
 import contextlib
 import datetime
 import imaplib
@@ -464,7 +464,6 @@ def _fetch_folder_list(self) -> List[Tuple[Tuple[bytes, ...], bytes, str]]:
         IMAPClient parses this response into a list of
         (flags, delimiter, name) tuples.
         """
-
         # As discovered in the wild list_folders() can return None as name,
         # we cannot handle those folders anyway so just filter them out.
         return [
@@ -656,7 +655,7 @@ def folders(self) -> List[RawFolder]:
         Fetch the list of folders for the account from the remote, return as a
         list of RawFolder objects.
 
-        NOTE:
+        Note:
         Always fetches the list of folders from the remote.
 
         """
@@ -709,7 +708,6 @@ def _get_missing_roles(
         Returns:
             a list of roles that did not appear as a role in folders
         """
-
         assert len(folders) > 0
         assert len(roles) > 0
 
@@ -1110,7 +1108,8 @@ def logout(self):
     def idle(self, timeout):
         """Idle for up to `timeout` seconds. Make sure we take the connection
         back out of idle mode so that we can reuse this connection in another
-        context."""
+        context.
+        """
         self.conn.idle()
         try:
             r = self.conn.idle_check(timeout)
@@ -1419,7 +1418,6 @@ def delete_draft(self, message_id_header):
 
         Leaves the Trash folder selected at the end of the method.
         """
-
         log.info("Trying to delete gmail draft", message_id_header=message_id_header)
         drafts_folder_name = self.folder_names()["drafts"][0]
         trash_folder_name = self.folder_names()["trash"][0]
diff --git a/inbox/error_handling.py b/inbox/error_handling.py
index b9e3f5f8a..3865ec1a9 100644
--- a/inbox/error_handling.py
+++ b/inbox/error_handling.py
@@ -31,7 +31,7 @@ def emit(self, record):
             "Uncaught error thrown by Flask/Werkzeug",
             "SyncbackWorker caught exception",
         ):
-            return
+            return None
 
         record.payload_data = {"fingerprint": event, "title": event}
 
diff --git a/inbox/events/actions/backends/gmail.py b/inbox/events/actions/backends/gmail.py
index 1e758e78d..b73991de6 100644
--- a/inbox/events/actions/backends/gmail.py
+++ b/inbox/events/actions/backends/gmail.py
@@ -1,4 +1,4 @@
-""" Operations for syncing back local Calendar changes to Gmail. """
+"""Operations for syncing back local Calendar changes to Gmail."""
 
 from inbox.events.google import GoogleEventsProvider
 
diff --git a/inbox/events/google.py b/inbox/events/google.py
index 0c3cb9cf9..8ebf0a00e 100644
--- a/inbox/events/google.py
+++ b/inbox/events/google.py
@@ -56,7 +56,6 @@ def sync_calendars(self) -> CalendarSyncResponse:
         """
         Fetch data for the user's calendars.
         """
-
         deletes = []
         updates = []
         items = self._get_raw_calendars()
diff --git a/inbox/events/ical.py b/inbox/events/ical.py
index 704cff9a2..f90619b96 100644
--- a/inbox/events/ical.py
+++ b/inbox/events/ical.py
@@ -773,9 +773,7 @@ def send_rsvp(ical_data, event, body_text, status, account):
     if status == "yes":
         msg.headers["Subject"] = f"Accepted: {event.message.subject}"
     elif status == "maybe":
-        msg.headers["Subject"] = "Tentatively accepted: {}".format(
-            event.message.subject
-        )
+        msg.headers["Subject"] = f"Tentatively accepted: {event.message.subject}"
     elif status == "no":
         msg.headers["Subject"] = f"Declined: {event.message.subject}"
 
diff --git a/inbox/events/microsoft/events_provider.py b/inbox/events/microsoft/events_provider.py
index 15357b87f..b8c20da61 100644
--- a/inbox/events/microsoft/events_provider.py
+++ b/inbox/events/microsoft/events_provider.py
@@ -217,7 +217,6 @@ def webhook_notifications_enabled(self, account: Account) -> bool:
         * https://learn.microsoft.com/en-us/answers/questions/417261/error-on-adding-subscription-on-events-using-ms-gr.html
         * https://stackoverflow.com/questions/65030751/ms-graph-adding-subscription-returns-extensionerror-and-serviceunavailable
         """
-
         # First check if we already have cached value since this function is called
         # repeatedly and there is no need to do extra HTTP request every time.
         if self._webhook_notifications_enabled is not None:
diff --git a/inbox/events/microsoft/graph_client.py b/inbox/events/microsoft/graph_client.py
index ad3add2ca..50923f6a9 100644
--- a/inbox/events/microsoft/graph_client.py
+++ b/inbox/events/microsoft/graph_client.py
@@ -224,7 +224,6 @@ def get_event(
             The event.
             https://learn.microsoft.com/en-us/graph/api/resources/event
         """
-
         params = {}
         if fields:
             params["$select"] = ",".join(fields)
@@ -324,7 +323,6 @@ def subscribe(
             The subscription.
             https://learn.microsoft.com/en-us/graph/api/resources/subscription
         """
-
         if resource_url.startswith(BASE_URL):
             resource_url = resource_url[len(BASE_URL) :]
 
@@ -449,7 +447,6 @@ def subscribe_to_event_changes(
             The subscription.
             https://learn.microsoft.com/en-us/graph/api/resources/subscription
         """
-
         return self.subscribe(
             resource_url=f"/me/calendars/{calendar_id}/events",
             change_types=[ChangeType.CREATED, ChangeType.UPDATED, ChangeType.DELETED],
diff --git a/inbox/events/recurring.py b/inbox/events/recurring.py
index a23e94919..dcfa38253 100644
--- a/inbox/events/recurring.py
+++ b/inbox/events/recurring.py
@@ -129,7 +129,7 @@ def get_start_times(event, start=None, end=None):
 
         rrules = parse_rrule(event)
         if not rrules:
-            log.warn("Tried to expand a non-recurring event", event_id=event.id)
+            log.warning("Tried to expand a non-recurring event", event_id=event.id)
             return [event.start]
 
         excl_dates = parse_exdate(event)
diff --git a/inbox/events/remote_sync.py b/inbox/events/remote_sync.py
index ec055439e..0d8c0680d 100644
--- a/inbox/events/remote_sync.py
+++ b/inbox/events/remote_sync.py
@@ -410,7 +410,6 @@ def _delete_calendar(db_session: Any, calendar: Calendar) -> None:
     processing (Transaction record creation) blocking the event loop.
 
     """
-
     # load ids first to save memory
     event_ids = [
         event_id
diff --git a/inbox/events/util.py b/inbox/events/util.py
index dc161c06d..ba3b72bb0 100644
--- a/inbox/events/util.py
+++ b/inbox/events/util.py
@@ -85,7 +85,8 @@ def valid_base36(uid):
 
 def removed_participants(original_participants, update_participants):
     """Returns the name and addresses of the participants which have been
-    removed."""
+    removed.
+    """
     original_table = {
         part["email"].lower(): part.get("name")
         for part in original_participants
diff --git a/inbox/heartbeat/store.py b/inbox/heartbeat/store.py
index 1890d08fb..649bae78f 100644
--- a/inbox/heartbeat/store.py
+++ b/inbox/heartbeat/store.py
@@ -96,7 +96,8 @@ def clear(self):
 
 class HeartbeatStore:
     """Store that proxies requests to Redis with handlers that also
-    update indexes and handle scanning through results."""
+    update indexes and handle scanning through results.
+    """
 
     _instances: Dict[Optional[str], "HeartbeatStore"] = {}
 
diff --git a/inbox/ignition.py b/inbox/ignition.py
index 531553f32..ddec933bd 100644
--- a/inbox/ignition.py
+++ b/inbox/ignition.py
@@ -206,11 +206,7 @@ def init_db(engine, key=0):
         event.listen(
             table,
             "after_create",
-            DDL(
-                "ALTER TABLE {tablename} AUTO_INCREMENT={increment}".format(
-                    tablename=table, increment=increment
-                )
-            ),
+            DDL(f"ALTER TABLE {table} AUTO_INCREMENT={increment}"),
         )
     with disabled_dubiously_many_queries_warning():
         MailSyncBase.metadata.create_all(engine)
@@ -260,9 +256,7 @@ def reset_invalid_autoincrements(engine, schema, key, dry_run=True):
         increment = engine.execute(query.format(schema, table)).scalar()
         if increment is not None and (increment >> 48) != key:
             if not dry_run:
-                reset_query = "ALTER TABLE {} AUTO_INCREMENT={}".format(
-                    table, (key << 48) + 1
-                )
+                reset_query = f"ALTER TABLE {table} AUTO_INCREMENT={(key << 48) + 1}"
                 engine.execute(reset_query)
             reset.add(str(table))
     return reset
diff --git a/inbox/instrumentation.py b/inbox/instrumentation.py
index 9ad2fddc3..e472f97e9 100644
--- a/inbox/instrumentation.py
+++ b/inbox/instrumentation.py
@@ -27,7 +27,8 @@
 class ProfileCollector:
     """A simple stack sampler for low-overhead CPU profiling: samples the call
     stack every `interval` seconds and keeps track of counts by frame. Because
-    this uses signals, it only works on the main thread."""
+    this uses signals, it only works on the main thread.
+    """
 
     def __init__(self, interval=0.005):
         self.interval = interval
diff --git a/inbox/logging.py b/inbox/logging.py
index 151512661..26bb5f06f 100644
--- a/inbox/logging.py
+++ b/inbox/logging.py
@@ -53,14 +53,16 @@ def find_first_app_frame_and_name(ignores=None):
 
 def _record_level(logger, name, event_dict):
     """Processor that records the log level ('info', 'warning', etc.) in the
-    structlog event dictionary."""
+    structlog event dictionary.
+    """
     event_dict["level"] = name
     return event_dict
 
 
 def _record_module(logger, name, event_dict):
     """Processor that records the module and line where the logging call was
-    invoked."""
+    invoked.
+    """
     f, name = find_first_app_frame_and_name(
         ignores=[
             "structlog",
@@ -78,7 +80,8 @@ def _record_module(logger, name, event_dict):
 def safe_format_exception(etype, value, tb, limit=None):
     """Similar to structlog._format_exception, but truncate the exception part.
     This is because SQLAlchemy exceptions can sometimes have ludicrously large
-    exception strings."""
+    exception strings.
+    """
     if tb:
         list = ["Traceback (most recent call last):\n"]
         list = list + traceback.format_tb(tb, limit)
diff --git a/inbox/mailsync/backends/gmail.py b/inbox/mailsync/backends/gmail.py
index 2583e6d9c..975f6a6d1 100644
--- a/inbox/mailsync/backends/gmail.py
+++ b/inbox/mailsync/backends/gmail.py
@@ -423,7 +423,8 @@ def __deduplicate_message_object_creation(self, db_session, raw_messages, accoun
     def add_message_to_thread(self, db_session, message_obj, raw_message):
         """Associate message_obj to the right Thread object, creating a new
         thread if necessary. We rely on Gmail's threading as defined by
-        X-GM-THRID instead of our threading algorithm."""
+        X-GM-THRID instead of our threading algorithm.
+        """
         # NOTE: g_thrid == g_msgid on the first message in the thread
         message_obj.g_msgid = raw_message.g_msgid
         message_obj.g_thrid = raw_message.g_thrid
@@ -438,7 +439,7 @@ def download_and_commit_uids(self, crispin_client, uids):
         start = datetime.utcnow()
         raw_messages = crispin_client.uids(uids)
         if not raw_messages:
-            return
+            return None
         new_uids = set()
         with self.syncmanager_lock, session_scope(self.namespace_id) as db_session:
             account = Account.get(self.account_id, db_session)
diff --git a/inbox/mailsync/backends/imap/generic.py b/inbox/mailsync/backends/imap/generic.py
index eef52fd60..664b7764a 100644
--- a/inbox/mailsync/backends/imap/generic.py
+++ b/inbox/mailsync/backends/imap/generic.py
@@ -602,7 +602,8 @@ def _count_thread_messages(self, thread_id, db_session):
 
     def add_message_to_thread(self, db_session, message_obj, raw_message):
         """Associate message_obj to the right Thread object, creating a new
-        thread if necessary."""
+        thread if necessary.
+        """
         with db_session.no_autoflush:
             # Disable autoflush so we don't try to flush a message with null
             # thread_id.
@@ -988,8 +989,6 @@ def uidvalidity_cb(self, account_id, folder_name, select_info):
 class UidInvalid(Exception):
     """Raised when a folder's UIDVALIDITY changes, requiring a resync."""
 
-    pass
-
 
 # This version is elsewhere in the codebase, so keep it for now
 # TODO(emfree): clean this up.
@@ -1009,9 +1008,7 @@ def uidvalidity_cb(
         )
         if not is_valid:
             raise UidInvalid(
-                "folder: {}, remote uidvalidity: {}, "
-                "cached uidvalidity: {}".format(
-                    folder_name, selected_uidvalidity, saved_uidvalidity
-                )
+                f"folder: {folder_name}, remote uidvalidity: {selected_uidvalidity}, "
+                f"cached uidvalidity: {saved_uidvalidity}"
             )
     return select_info
diff --git a/inbox/mailsync/frontend.py b/inbox/mailsync/frontend.py
index 5b2aea14a..f9934da9a 100644
--- a/inbox/mailsync/frontend.py
+++ b/inbox/mailsync/frontend.py
@@ -11,7 +11,8 @@ class ProfilingHTTPFrontend:
     """This is a lightweight embedded HTTP server that runs inside a mailsync
     or syncback process. It allows you to programmatically interact with the
     process: to get profile/memory/load metrics, or to schedule new account
-    syncs."""
+    syncs.
+    """
 
     def __init__(self, port, trace_greenlets, profile):
         self.port = port
@@ -108,4 +109,3 @@ def build_metadata():
 class _QuietHandler(WSGIRequestHandler):
     def log_request(self, *args, **kwargs):
         """Suppress request logging so as not to pollute application logs."""
-        pass
diff --git a/inbox/mailsync/service.py b/inbox/mailsync/service.py
index a3b6b9409..45a248628 100644
--- a/inbox/mailsync/service.py
+++ b/inbox/mailsync/service.py
@@ -200,9 +200,7 @@ def poll(self):
         # Determine which accounts to sync
         start_accounts = self.account_ids_to_sync()
         statsd_client.gauge(
-            "mailsync.account_counts.{}.mailsync-{}.count".format(
-                self.host, self.process_number
-            ),
+            f"mailsync.account_counts.{self.host}.mailsync-{self.process_number}.count",
             len(start_accounts),
         )
 
@@ -377,7 +375,6 @@ def stop_sync(self, account_id):
         If that account doesn't exist, does nothing.
 
         """
-
         with self.semaphore:
             self.log.info("Stopping monitors", account_id=account_id)
             if account_id in self.email_sync_monitors:
diff --git a/inbox/models/backends/imap.py b/inbox/models/backends/imap.py
index b584cad87..d28ee36ea 100644
--- a/inbox/models/backends/imap.py
+++ b/inbox/models/backends/imap.py
@@ -125,7 +125,7 @@ class ImapUid(MailSyncBase, UpdatedAtMixin, DeletedAtMixin):
     extra_flags = Column(LittleJSON, default=[], nullable=False)
     # labels (Gmail-specific)
     # TO BE DEPRECATED
-    g_labels = Column(JSON, default=lambda: [], nullable=True)
+    g_labels = Column(JSON, default=list, nullable=True)
 
     def update_flags(self, new_flags: List[bytes]) -> None:
         """
diff --git a/inbox/models/backends/oauth.py b/inbox/models/backends/oauth.py
index a53863270..3dec74500 100644
--- a/inbox/models/backends/oauth.py
+++ b/inbox/models/backends/oauth.py
@@ -189,6 +189,7 @@ def new_token(
         Args:
             force_refresh (bool): Whether a token refresh should be forced when
                 requesting it from an external token service (AuthAlligator)
+
         Returns:
             A tuple with the new access token and its expiration.
 
diff --git a/inbox/models/category.py b/inbox/models/category.py
index be12f732d..4e7213bcf 100644
--- a/inbox/models/category.py
+++ b/inbox/models/category.py
@@ -115,8 +115,8 @@ def find_or_create(cls, session, namespace_id, name, display_name, type_):
                 obj.name = name
         else:
             log.error(
-                "Duplicate category rows for namespace_id {}, "
-                "name {}, display_name: {}".format(namespace_id, name, display_name)
+                f"Duplicate category rows for namespace_id {namespace_id}, "
+                f"name {name}, display_name: {display_name}"
             )
             raise MultipleResultsFound(
                 "Duplicate category rows for namespace_id {}, name {}, "
diff --git a/inbox/models/event.py b/inbox/models/event.py
index 576427fc8..0c9a2d6dd 100644
--- a/inbox/models/event.py
+++ b/inbox/models/event.py
@@ -247,7 +247,6 @@ def _partial_participants_merge(self, event):
         It would be very wrong to call this method to merge, say, Google
         Events participants because they handle the merging themselves.
         """
-
         # We have to jump through some hoops because a participant may
         # not have an email or may not have a name, so we build a hash
         # where we can find both. Also note that we store names in the
@@ -334,7 +333,7 @@ def recurring(self):
                     r = [r]
                 return r
             except (ValueError, SyntaxError):
-                log.warn(
+                log.warning(
                     "Invalid RRULE entry for event",
                     event_id=self.id,
                     raw_rrule=self.recurrence,
@@ -392,7 +391,7 @@ def calendar_event_link(self):
         try:
             return json.loads(self.raw_data)["htmlLink"]
         except (ValueError, KeyError):
-            return
+            return None
 
     @property
     def emails_from_description(self):
@@ -426,8 +425,8 @@ def create(cls, **kwargs):
 
     def __init__(self, **kwargs):
         if (
-            not kwargs.pop("__event_created_sanely", None)
-            is _EVENT_CREATED_SANELY_SENTINEL
+            kwargs.pop("__event_created_sanely", None)
+            is not _EVENT_CREATED_SANELY_SENTINEL
         ):
             raise AssertionError(
                 "Use Event.create with appropriate keyword args "
@@ -629,7 +628,7 @@ def update(self, master):
 
 
 def insert_warning(mapper, connection, target):
-    log.warn(f"InflatedEvent {target} shouldn't be committed")
+    log.warning(f"InflatedEvent {target} shouldn't be committed")
     raise Exception("InflatedEvent should not be committed")
 
 
diff --git a/inbox/models/folder.py b/inbox/models/folder.py
index 70195ba8b..863277b19 100644
--- a/inbox/models/folder.py
+++ b/inbox/models/folder.py
@@ -99,11 +99,7 @@ def find_or_create(cls, session, account, name, role=None):
             )
             session.add(obj)
         except MultipleResultsFound:
-            log.info(
-                "Duplicate folder rows for name {}, account_id {}".format(
-                    name, account.id
-                )
-            )
+            log.info(f"Duplicate folder rows for name {name}, account_id {account.id}")
             raise
 
         return obj
diff --git a/inbox/models/message.py b/inbox/models/message.py
index ad2bb4a70..34aa5b136 100644
--- a/inbox/models/message.py
+++ b/inbox/models/message.py
@@ -130,12 +130,12 @@ def thread(self, value):
 
     thread = synonym("_thread", descriptor=thread)
 
-    from_addr = Column(JSON, nullable=False, default=lambda: [])
+    from_addr = Column(JSON, nullable=False, default=list)
     sender_addr = Column(JSON, nullable=True)
-    reply_to = Column(JSON, nullable=True, default=lambda: [])
-    to_addr = Column(JSON, nullable=False, default=lambda: [])
-    cc_addr = Column(JSON, nullable=False, default=lambda: [])
-    bcc_addr = Column(JSON, nullable=False, default=lambda: [])
+    reply_to = Column(JSON, nullable=True, default=list)
+    to_addr = Column(JSON, nullable=False, default=list)
+    cc_addr = Column(JSON, nullable=False, default=list)
+    bcc_addr = Column(JSON, nullable=False, default=list)
     in_reply_to = Column(JSON, nullable=True)
     # From: http://tools.ietf.org/html/rfc4130, section 5.3.3,
     # max message_id_header is 998 characters
@@ -221,8 +221,8 @@ def regenerate_nylas_uid(self) -> None:
         The value of nylas_uid is simply the draft public_id and version,
         concatenated. Because the nylas_uid identifies the draft on the remote
         provider, we regenerate it on each draft revision so that we can delete
-        the old draft and add the new one on the remote."""
-
+        the old draft and add the new one on the remote.
+        """
         from inbox.sendmail.message import generate_message_id_header
 
         self.nylas_uid = f"{self.public_id}-{self.version}"
diff --git a/inbox/models/roles.py b/inbox/models/roles.py
index 1d853ae54..b6071de45 100644
--- a/inbox/models/roles.py
+++ b/inbox/models/roles.py
@@ -48,9 +48,7 @@ def data(self):
                 message = self.parts[0].message  # only grab one
                 account = message.namespace.account
 
-                statsd_string = "api.direct_fetching.{}.{}".format(
-                    account.provider, account.id
-                )
+                statsd_string = f"api.direct_fetching.{account.provider}.{account.id}"
 
                 # Try to fetch the message from S3 first.
                 with statsd_client.timer(f"{statsd_string}.blockstore_latency"):
diff --git a/inbox/models/session.py b/inbox/models/session.py
index f04ccae76..b836ef165 100644
--- a/inbox/models/session.py
+++ b/inbox/models/session.py
@@ -119,7 +119,6 @@ def after_flush(session, flush_context):
             bump_redis_txn_id(session)
         except Exception:
             log.exception("bump_redis_txn_id exception")
-            pass
         create_revisions(session)
 
     return session
@@ -177,7 +176,7 @@ def session_scope(id_, versioned=True):
             session.rollback()
             raise
         except OperationalError:
-            log.warn(
+            log.warning(
                 "Encountered OperationalError on rollback", original_exception=type(exc)
             )
             raise exc
diff --git a/inbox/models/util.py b/inbox/models/util.py
index 2e41ebd58..f7eab3141 100644
--- a/inbox/models/util.py
+++ b/inbox/models/util.py
@@ -166,7 +166,6 @@ def delete_namespace(namespace_id, throttle=False, dry_run=False):
 
     Raises AccountDeletionErrror with message if there are problems
     """
-
     with session_scope(namespace_id) as db_session:
         try:
             account = (
@@ -296,13 +295,11 @@ def _batch_delete(
     if table in ("message", "block"):
         query = ""
     else:
-        query = "DELETE FROM {} WHERE {}={} LIMIT {};".format(
-            table, column, id_, CHUNK_SIZE
-        )
+        query = f"DELETE FROM {table} WHERE {column}={id_} LIMIT {CHUNK_SIZE};"
 
     log.info("deleting", account_id=account_id, table=table)
 
-    for _ in range(0, batches):
+    for _ in range(batches):
         if throttle:
             bulk_throttle()
 
@@ -405,12 +402,12 @@ def purge_transactions(
         offset = 0
         query = (
             "SELECT id FROM transaction where created_at < "
-            "DATE_SUB({}, INTERVAL {} day) LIMIT {}".format(start, days_ago, limit)
+            f"DATE_SUB({start}, INTERVAL {days_ago} day) LIMIT {limit}"
         )
     else:
         query = (
-            "DELETE FROM transaction where created_at < DATE_SUB({},"
-            " INTERVAL {} day) LIMIT {}".format(start, days_ago, limit)
+            f"DELETE FROM transaction where created_at < DATE_SUB({start},"
+            f" INTERVAL {days_ago} day) LIMIT {limit}"
         )
     try:
         # delete from rows until there are no more rows affected
diff --git a/inbox/s3/backends/gmail.py b/inbox/s3/backends/gmail.py
index b6cc76af6..f0a7bdb72 100644
--- a/inbox/s3/backends/gmail.py
+++ b/inbox/s3/backends/gmail.py
@@ -29,9 +29,7 @@ def get_gmail_raw_contents(message):
         g_msgid = int(g_msgid)
 
     hex_id = format(g_msgid, "x")
-    url = "https://www.googleapis.com/gmail/v1/users/me/messages/{}?format=raw".format(
-        hex_id
-    )
+    url = f"https://www.googleapis.com/gmail/v1/users/me/messages/{hex_id}?format=raw"
     r = requests.get(url, auth=OAuthRequestsWrapper(auth_token))
 
     if r.status_code != 200:
diff --git a/inbox/s3/exc.py b/inbox/s3/exc.py
index e2393773c..7983da649 100644
--- a/inbox/s3/exc.py
+++ b/inbox/s3/exc.py
@@ -9,11 +9,8 @@ class EmailFetchException(S3Exception):
 class EmailDeletedException(EmailFetchException):
     """Raises an error when the message is deleted on the remote."""
 
-    pass
-
 
 class TemporaryEmailFetchException(EmailFetchException):
     """A class for temporary errors when trying to fetch emails.
-    Exchange notably seems to need warming up before fetching data."""
-
-    pass
+    Exchange notably seems to need warming up before fetching data.
+    """
diff --git a/inbox/search/backends/imap.py b/inbox/search/backends/imap.py
index de29709a3..6ddb05d22 100644
--- a/inbox/search/backends/imap.py
+++ b/inbox/search/backends/imap.py
@@ -51,7 +51,9 @@ def _open_crispin_connection(self, db_session):
         try:
             acct_provider_info = provider_info(account.provider)
         except NotSupportedError:
-            self.log.warn("Account provider not supported", provider=account.provider)
+            self.log.warning(
+                "Account provider not supported", provider=account.provider
+            )
             raise
 
         self.crispin_client = CrispinClient(
@@ -199,7 +201,7 @@ def _search_folder(self, folder, criteria, charset):
         try:
             self.crispin_client.select_folder(folder.name, uidvalidity_cb)
         except FolderMissingError:
-            self.log.warn("Won't search missing IMAP folder", exc_info=True)
+            self.log.warning("Won't search missing IMAP folder", exc_info=True)
             return []
         except UidInvalid:
             self.log.error(
@@ -210,7 +212,7 @@ def _search_folder(self, folder, criteria, charset):
         try:
             uids = self.crispin_client.conn.search(criteria, charset=charset)
         except IMAP4.error:
-            self.log.warn("Search error", exc_info=True)
+            self.log.warning("Search error", exc_info=True)
             raise SearchBackendException(
                 ("Unknown IMAP error when performing search."), 503
             )
diff --git a/inbox/search/base.py b/inbox/search/base.py
index 07aaff055..c3a6e67bd 100644
--- a/inbox/search/base.py
+++ b/inbox/search/base.py
@@ -9,7 +9,8 @@ def get_search_client(account):
 
 class SearchBackendException(Exception):
     """Raised if there's an error proxying the search request to the
-    provider."""
+    provider.
+    """
 
     def __init__(self, message, http_code, server_error=None):
         self.message = message
@@ -24,7 +25,8 @@ def __str__(self):
 class SearchStoreException(Exception):
     """Raised if there's an error proxying the search request to the provider.
     This is a special EAS case where the Status code for the Store element has
-    an error"""
+    an error
+    """
 
     def __init__(self, err_code):
         self.err_code = err_code
diff --git a/inbox/security/oracles.py b/inbox/security/oracles.py
index d43fa4800..dd6598c1a 100644
--- a/inbox/security/oracles.py
+++ b/inbox/security/oracles.py
@@ -151,7 +151,6 @@ def decrypt(self, ciphertext, encryption_scheme):
 
         Returns the plaintext as bytes.
         """
-
         if self._closed:
             raise ValueError("Connection to crypto oracle already closed")
 
diff --git a/inbox/sendmail/base.py b/inbox/sendmail/base.py
index 1f8d82468..3a1e078c1 100644
--- a/inbox/sendmail/base.py
+++ b/inbox/sendmail/base.py
@@ -55,14 +55,10 @@ def create_draft_from_mime(
 ) -> Message:
     our_uid = generate_public_id()  # base-36 encoded string
     new_headers = (
-        (
-            "X-INBOX-ID: {0}-0\r\n"
-            "Message-Id: <{0}-0@mailer.nylas.com>\r\n"
-            "User-Agent: NylasMailer/{1}\r\n"
-        )
-        .format(our_uid, VERSION)
-        .encode()
-    )
+        f"X-INBOX-ID: {our_uid}-0\r\n"
+        f"Message-Id: <{our_uid}-0@mailer.nylas.com>\r\n"
+        f"User-Agent: NylasMailer/{VERSION}\r\n"
+    ).encode()
     new_body = new_headers + raw_mime
 
     with db_session.no_autoflush:
@@ -117,8 +113,8 @@ def block_to_part(block, message, namespace):
 def create_message_from_json(data, namespace, db_session, is_draft):
     """Construct a Message instance from `data`, a dictionary representing the
     POST body of an API request. All new objects are added to the session, but
-    not committed."""
-
+    not committed.
+    """
     # Validate the input and get referenced objects (thread, attachments)
     # as necessary.
     to_addr = get_recipients(data.get("to"), "to")
@@ -382,7 +378,8 @@ def generate_attachments(message, blocks):
 
 def _set_reply_headers(new_message, previous_message):
     """When creating a draft in reply to a thread, set the In-Reply-To and
-    References headers appropriately, if possible."""
+    References headers appropriately, if possible.
+    """
     if previous_message.message_id_header:
         new_message.in_reply_to = previous_message.message_id_header
         if previous_message.references:
diff --git a/inbox/sendmail/message.py b/inbox/sendmail/message.py
index 4ad87f856..9a297914d 100644
--- a/inbox/sendmail/message.py
+++ b/inbox/sendmail/message.py
@@ -214,7 +214,6 @@ def add_nylas_headers(msg, nylas_uid):
     public_id of the message object.
 
     """
-
     # Set our own custom header for tracking in `Sent Mail` folder
     msg.headers["X-INBOX-ID"] = nylas_uid
     msg.headers["Message-Id"] = generate_message_id_header(nylas_uid)
diff --git a/inbox/sendmail/smtp/postel.py b/inbox/sendmail/smtp/postel.py
index 4434a81ac..6ae60cf44 100644
--- a/inbox/sendmail/smtp/postel.py
+++ b/inbox/sendmail/smtp/postel.py
@@ -107,7 +107,6 @@ def _substitute_bcc(raw_message: bytes) -> bytes:
     """
     Substitute BCC in raw message.
     """
-
     bcc_regexp = re.compile(rb"^Bcc: [^\r\n]*\r\n", re.IGNORECASE | re.MULTILINE)
     return bcc_regexp.sub(b"", raw_message)
 
@@ -201,9 +200,9 @@ def _smtp_oauth2_try_refresh(self):
             )
 
     def _try_xoauth2(self):
-        auth_string = "user={}\1auth=Bearer {}\1\1".format(
-            self.email_address, self.auth_token
-        ).encode()
+        auth_string = (
+            f"user={self.email_address}\1auth=Bearer {self.auth_token}\1\1".encode()
+        )
         code, resp = self.connection.docmd(
             "AUTH", f"XOAUTH2 {base64.b64encode(auth_string).decode()}"
         )
diff --git a/inbox/sqlalchemy_ext/util.py b/inbox/sqlalchemy_ext/util.py
index 858ff0d8b..60a0a5f73 100644
--- a/inbox/sqlalchemy_ext/util.py
+++ b/inbox/sqlalchemy_ext/util.py
@@ -69,7 +69,8 @@ def before_commit(conn):
 class ABCMixin:
     """Use this if you want a mixin class which is actually an abstract base
     class, for example in order to enforce that concrete subclasses define
-    particular methods or properties."""
+    particular methods or properties.
+    """
 
     __abstract__ = True
 
diff --git a/inbox/transactions/actions.py b/inbox/transactions/actions.py
index f27516cd0..a7cf36ecb 100644
--- a/inbox/transactions/actions.py
+++ b/inbox/transactions/actions.py
@@ -147,7 +147,7 @@ def __init__(
                 and key % total_processes == process_number
             ]
         else:
-            self.log.warn(
+            self.log.warning(
                 "No shards assigned to syncback server", syncback_id=syncback_id
             )
             self.keys = []
@@ -307,7 +307,7 @@ def _get_batch_task(self, db_session, log_entries, has_more):
         valid log entries.
         """
         if not log_entries:
-            return
+            return None
         namespace = log_entries[0].namespace
         account_id = namespace.account.id
         semaphore = self.account_semaphores[account_id]
@@ -414,13 +414,13 @@ def _batch_log_entries(self, db_session, log_entries):
                         action_log_id=log_entry.id,
                         retries=log_entry.retries,
                     )
-                    return
+                    return None
 
             valid_log_entries.append(log_entry)
 
         batch_task = self._get_batch_task(db_session, valid_log_entries, has_more)
         if not batch_task:
-            return
+            return None
         for task in batch_task.tasks:
             self.running_action_ids.update(task.action_log_ids)
             self.log.debug(
diff --git a/inbox/transactions/delta_sync.py b/inbox/transactions/delta_sync.py
index 7e944ac6e..99e9a0885 100644
--- a/inbox/transactions/delta_sync.py
+++ b/inbox/transactions/delta_sync.py
@@ -277,6 +277,7 @@ def streaming_change_generator(
     """
     Poll the transaction log for the given `namespace_id` until `timeout`
     expires, and yield each time new entries are detected.
+
     Arguments
     ---------
     namespace_id: int
diff --git a/inbox/transactions/search.py b/inbox/transactions/search.py
index 093cdfab8..7e45674cd 100644
--- a/inbox/transactions/search.py
+++ b/inbox/transactions/search.py
@@ -75,7 +75,7 @@ def _set_transaction_pointers(self):
                         self.transaction_pointers[key] = 0
 
     def _index_transactions(self, namespace_ids=None):
-        """index with filter"""
+        """Index with filter"""
         # index 'em
         for key in engine_manager.engines:
             shard_should_sleep = []
diff --git a/inbox/util/__init__.py b/inbox/util/__init__.py
index f1000f72e..1f9e36ac7 100644
--- a/inbox/util/__init__.py
+++ b/inbox/util/__init__.py
@@ -1,6 +1,6 @@
-""" Non-server-specific utility modules. These shouldn't depend on any code
-    from the inbox module tree!
+"""Non-server-specific utility modules. These shouldn't depend on any code
+from the inbox module tree!
 
-    Don't add new code here! Find the relevant submodule, or use misc.py if
-    there's really no other place.
+Don't add new code here! Find the relevant submodule, or use misc.py if
+there's really no other place.
 """
diff --git a/inbox/util/blockstore.py b/inbox/util/blockstore.py
index dd4011bcd..079b40c8b 100644
--- a/inbox/util/blockstore.py
+++ b/inbox/util/blockstore.py
@@ -142,7 +142,7 @@ def _get_from_s3_bucket(data_sha256, bucket_name):
 
     if not key:
         log.warning(f"No key with name: {data_sha256} returned!")
-        return
+        return None
 
     return key.get_contents_as_string()
 
@@ -156,13 +156,13 @@ def _get_from_disk(data_sha256):
             return f.read()
     except OSError:
         log.warning(f"No file with name: {data_sha256}!")
-        return
+        return None
 
 
 def _delete_from_s3_bucket(data_sha256_hashes, bucket_name):
     data_sha256_hashes = [hash_ for hash_ in data_sha256_hashes if hash_]
     if not data_sha256_hashes:
-        return None
+        return
 
     assert "AWS_ACCESS_KEY_ID" in config, "Need AWS key!"
     assert "AWS_SECRET_ACCESS_KEY" in config, "Need AWS secret!"
@@ -180,7 +180,7 @@ def _delete_from_s3_bucket(data_sha256_hashes, bucket_name):
 
 def _delete_from_disk(data_sha256):
     if not data_sha256:
-        return None
+        return
 
     try:
         os.remove(_data_file_path(data_sha256))
diff --git a/inbox/util/db.py b/inbox/util/db.py
index 9f4e42868..3876143c8 100644
--- a/inbox/util/db.py
+++ b/inbox/util/db.py
@@ -15,7 +15,6 @@ def drop_everything(engine, keep_tables=None, reset_columns=None):
     default value in the tables that we're keeping -
     provided as a dict of table_name: list_of_column_names.
     """
-
     keep_tables = keep_tables or []
     reset_columns = reset_columns or {}
     conn = engine.connect()
diff --git a/inbox/util/debug.py b/inbox/util/debug.py
index c9e9d18ef..bfecae3b3 100644
--- a/inbox/util/debug.py
+++ b/inbox/util/debug.py
@@ -23,7 +23,8 @@ def wrapper(*args, **kwargs):
 def attach_pyinstrument_profiler():
     """Run the pyinstrument profiler in the background and dump its output to
     stdout when the process receives SIGTRAP. In general, you probably want to
-    use the facilities in inbox.util.profiling instead."""
+    use the facilities in inbox.util.profiling instead.
+    """
     profiler = Profiler()
     profiler.start()
 
diff --git a/inbox/util/misc.py b/inbox/util/misc.py
index 1adda8392..6a97dc112 100644
--- a/inbox/util/misc.py
+++ b/inbox/util/misc.py
@@ -145,7 +145,8 @@ def register_backends(base_name, base_path):
 
 def cleanup_subject(subject_str):
     """Clean-up a message subject-line, including whitespace.
-    For instance, 'Re: Re: Re: Birthday   party' becomes 'Birthday party'"""
+    For instance, 'Re: Re: Re: Birthday   party' becomes 'Birthday party'
+    """
     if subject_str is None:
         return ""
     # TODO consider expanding to all
diff --git a/inbox/util/testutils.py b/inbox/util/testutils.py
index f59a646cf..37aff4105 100644
--- a/inbox/util/testutils.py
+++ b/inbox/util/testutils.py
@@ -42,15 +42,14 @@ def create_test_db():
 
     for name, host, user, password in schemas:
         cmd = (
-            "DROP DATABASE IF EXISTS {name}; "
-            "CREATE DATABASE IF NOT EXISTS {name} "
+            f"DROP DATABASE IF EXISTS {name}; "
+            f"CREATE DATABASE IF NOT EXISTS {name} "
             "DEFAULT CHARACTER SET utf8mb4 DEFAULT COLLATE "
-            "utf8mb4_general_ci".format(name=name)
+            "utf8mb4_general_ci"
         )
 
         subprocess.check_call(
-            "mysql -h {} -u{} -p{} " '-e "{}"'.format(host, user, password, cmd),
-            shell=True,
+            f"mysql -h {host} -u{user} -p{password} " f'-e "{cmd}"', shell=True
         )
 
 
@@ -137,7 +136,8 @@ def mock_query(self, domain, record_type):
 
 class MockIMAPClient:
     """A bare-bones stand-in for an IMAPClient instance, used to test sync
-    logic without requiring a real IMAP account and server."""
+    logic without requiring a real IMAP account and server.
+    """
 
     def __init__(self):
         self._data = {}
diff --git a/inbox/util/threading.py b/inbox/util/threading.py
index 4f16a64c9..36ccd7f61 100644
--- a/inbox/util/threading.py
+++ b/inbox/util/threading.py
@@ -12,8 +12,9 @@
 
 
 def fetch_corresponding_thread(db_session, namespace_id, message):
-    """fetch a thread matching the corresponding message. Returns None if
-    there's no matching thread."""
+    """Fetch a thread matching the corresponding message. Returns None if
+    there's no matching thread.
+    """
     # handle the case where someone is self-sending an email.
     if not message.from_addr or not message.to_addr:
         return None
diff --git a/inbox/util/url.py b/inbox/util/url.py
index 697944434..df6602969 100644
--- a/inbox/util/url.py
+++ b/inbox/util/url.py
@@ -196,7 +196,6 @@ def matching_subdomains(new_value, old_value):
     2. shares the same top-level domain name.
 
     """
-
     if new_value is None and old_value is not None:
         return False
 
diff --git a/inbox/webhooks/microsoft_notifications.py b/inbox/webhooks/microsoft_notifications.py
index c517ba815..33075ed5f 100644
--- a/inbox/webhooks/microsoft_notifications.py
+++ b/inbox/webhooks/microsoft_notifications.py
@@ -60,7 +60,6 @@ def _validate_webhook_payload(*args, **kwargs):
             have two separate endpoints, one for calendar changes and one for
             event changes.
             """
-
             try:
                 request.json
             except UnsupportedMediaType:
diff --git a/migrations/versions/000_g_msgid_g_thrid_as_integers.py b/migrations/versions/000_g_msgid_g_thrid_as_integers.py
index 4f2cf607a..18bca8784 100644
--- a/migrations/versions/000_g_msgid_g_thrid_as_integers.py
+++ b/migrations/versions/000_g_msgid_g_thrid_as_integers.py
@@ -1,4 +1,4 @@
-""" Store g_msgid and g_thrid as integers, not strings. For more efficiency.
+"""Store g_msgid and g_thrid as integers, not strings. For more efficiency.
 
 Revision ID: 2605b23e1fe6
 Revises: None
diff --git a/migrations/versions/002_store_g_thrid_as_biginteger_instead_of_.py b/migrations/versions/002_store_g_thrid_as_biginteger_instead_of_.py
index eed33afe4..02737e0cb 100644
--- a/migrations/versions/002_store_g_thrid_as_biginteger_instead_of_.py
+++ b/migrations/versions/002_store_g_thrid_as_biginteger_instead_of_.py
@@ -1,4 +1,4 @@
-""" Change g_thrid as BigInteger instead of string
+"""Change g_thrid as BigInteger instead of string
 
 Revision ID: 297aa1e1acc7
 Revises: 217431caacc7
diff --git a/migrations/versions/005_import_old_accounts.py b/migrations/versions/005_import_old_accounts.py
index f5fcefa30..6556cbd8e 100644
--- a/migrations/versions/005_import_old_accounts.py
+++ b/migrations/versions/005_import_old_accounts.py
@@ -23,7 +23,7 @@ def upgrade():
     from inbox.models.session import session_scope
 
     engine = main_engine(pool_size=1, max_overflow=0)
-    import inbox.auth.gmail as gmail
+    from inbox.auth import gmail
     from inbox.models.backends.imap import ImapAccount
 
     # Assert we have the dump file
@@ -36,7 +36,7 @@ def upgrade():
         return
 
     # Imports to `imapaccount_old` table
-    with open(SQL_DUMP_FILENAME, "r") as f:
+    with open(SQL_DUMP_FILENAME) as f:
         print("Importing old account data..."),
         op.execute(f.read())
         print("OK!")
@@ -51,13 +51,13 @@ class ImapAccount_Old(Base):
         migrated_accounts = []
 
         for acct in db_session.query(ImapAccount_Old):
-            print("Importing {0}".format(acct.email_address))
+            print(f"Importing {acct.email_address}")
 
             existing_account = db_session.query(ImapAccount).filter_by(
                 email_address=acct.email_address
             )
             if existing_account.count() > 0:
-                print("Already have account for {0}".format(acct.email_address))
+                print(f"Already have account for {acct.email_address}")
                 continue
 
             # Create a mock OAuth response using data from the old table
@@ -86,23 +86,19 @@ class ImapAccount_Old(Base):
             db_session.commit()
             migrated_accounts.append(new_account)
 
-        print("\nDone! Imported {0} accounts.".format(len(migrated_accounts)))
+        print(f"\nDone! Imported {len(migrated_accounts)} accounts.")
         print("\nNow verifying refresh tokens...\n")
 
         verified_accounts = []
         for acct in migrated_accounts:
-            print("Verifying {0}... ".format(acct.email_address)),
+            print(f"Verifying {acct.email_address}... "),
             if gmail.verify_account(acct):
                 verified_accounts.append(acct)
                 print("OK!")
             else:
                 print("FAILED!")
 
-        print(
-            "Done! Verified {0} of {1}".format(
-                len(verified_accounts), len(migrated_accounts)
-            )
-        )
+        print(f"Done! Verified {len(verified_accounts)} of {len(migrated_accounts)}")
 
     op.drop_table("imapaccount_old")
 
diff --git a/migrations/versions/017_haspublicid.py b/migrations/versions/017_haspublicid.py
index 1430124c8..1245d9410 100644
--- a/migrations/versions/017_haspublicid.py
+++ b/migrations/versions/017_haspublicid.py
@@ -52,7 +52,7 @@ def upgrade():
 
     for c in classes:
         assert issubclass(c, HasPublicID)
-        print("[{0}] adding public_id column... ".format(c.__tablename__)),
+        print(f"[{c.__tablename__}] adding public_id column... "),
         sys.stdout.flush()
         op.add_column(
             c.__tablename__, sa.Column("public_id", mysql.BINARY(16), nullable=False)
@@ -60,7 +60,7 @@ def upgrade():
 
         print("adding index... "),
         op.create_index(
-            "ix_{0}_public_id".format(c.__tablename__),
+            f"ix_{c.__tablename__}_public_id",
             c.__tablename__,
             ["public_id"],
             unique=False,
@@ -75,7 +75,7 @@ def upgrade():
         count = 0
         for c in classes:
             garbage_collect()
-            print("[{0}] Loading rows. ".format(c.__name__)),
+            print(f"[{c.__name__}] Loading rows. "),
             sys.stdout.flush()
             print("Generating public_ids"),
             sys.stdout.flush()
@@ -87,7 +87,7 @@ def upgrade():
                     sys.stdout.flush()
                     db_session.commit()
                     garbage_collect()
-            sys.stdout.write(" Saving. ".format(c.__name__)),
+            sys.stdout.write(" Saving. ".format()),
             # sys.stdout.flush()
             sys.stdout.flush()
             db_session.commit()
@@ -125,12 +125,10 @@ def downgrade():
 
     for c in classes:
         assert issubclass(c, HasPublicID)
-        print("[{0}] Dropping public_id column... ".format(c.__tablename__)),
+        print(f"[{c.__tablename__}] Dropping public_id column... "),
         op.drop_column(c.__tablename__, "public_id")
 
         print("Dropping index... "),
-        op.drop_index(
-            "ix_{0}_public_id".format(c.__tablename__), table_name=c.__tablename__
-        )
+        op.drop_index(f"ix_{c.__tablename__}_public_id", table_name=c.__tablename__)
 
         print("Done.")
diff --git a/migrations/versions/022_webhooks_and_filters.py b/migrations/versions/022_webhooks_and_filters.py
index b0d653d72..6726a485f 100644
--- a/migrations/versions/022_webhooks_and_filters.py
+++ b/migrations/versions/022_webhooks_and_filters.py
@@ -1,4 +1,4 @@
-""" Rename WebhookParameters -> Webhook
+"""Rename WebhookParameters -> Webhook
 
 Note that this migration deletes old webhook data.
 This is OK because we haven't stored any webhooks yet.
diff --git a/migrations/versions/038_add_public_ids_to_transactions.py b/migrations/versions/038_add_public_ids_to_transactions.py
index b57856d65..79ee9a523 100644
--- a/migrations/versions/038_add_public_ids_to_transactions.py
+++ b/migrations/versions/038_add_public_ids_to_transactions.py
@@ -47,7 +47,7 @@ class Transaction(Base):
     with session_scope(versioned=False) as db_session:
         count = 0
         (num_transactions,) = db_session.query(sa.func.max(Transaction.id)).one()
-        print("Adding public ids to {} transactions".format(num_transactions))
+        print(f"Adding public ids to {num_transactions} transactions")
         for pointer in range(0, num_transactions + 1, 500):
             for entry in db_session.query(Transaction).filter(
                 Transaction.id >= pointer, Transaction.id < pointer + 500
diff --git a/migrations/versions/045_new_password_storage.py b/migrations/versions/045_new_password_storage.py
index 344bbe73f..119f79079 100644
--- a/migrations/versions/045_new_password_storage.py
+++ b/migrations/versions/045_new_password_storage.py
@@ -73,12 +73,12 @@ def _keyfile(self, create_dir=True):
                 assert KEY_DIR
                 if create_dir:
                     mkdirp(KEY_DIR)
-                key_filename = "{0}".format(sha256(self.key).hexdigest())
+                key_filename = f"{sha256(self.key).hexdigest()}"
                 return os.path.join(KEY_DIR, key_filename)
 
             def get_old_password(self):
                 if self.password_aes is not None:
-                    with open(self._keyfile, "r") as f:
+                    with open(self._keyfile) as f:
                         key = f.read()
 
                     key = self.key + key
diff --git a/migrations/versions/056_message_unique_constraint.py b/migrations/versions/056_message_unique_constraint.py
index 719cdaffd..d2b00c9a8 100644
--- a/migrations/versions/056_message_unique_constraint.py
+++ b/migrations/versions/056_message_unique_constraint.py
@@ -1,4 +1,4 @@
-""" Remove duplicated Gmail Message objects and tighten constraints for Gmail messages.
+"""Remove duplicated Gmail Message objects and tighten constraints for Gmail messages.
 
 Revision ID: 4b4c5579c083
 Revises: 1925c535a52d
@@ -65,9 +65,7 @@ def upgrade():
 
         for message_id, thread_id, g_msgid in groups:
             print(
-                "deleting duplicates of ({}, {}), saving {}".format(
-                    thread_id, g_msgid, message_id
-                )
+                f"deleting duplicates of ({thread_id}, {g_msgid}), saving {message_id}"
             )
             db_session.query(Message).filter(
                 Message.thread_id == thread_id,
diff --git a/migrations/versions/089_revert_encryption.py b/migrations/versions/089_revert_encryption.py
index 3ad843533..ddb051791 100644
--- a/migrations/versions/089_revert_encryption.py
+++ b/migrations/versions/089_revert_encryption.py
@@ -1,4 +1,4 @@
-""" Revert encryption
+"""Revert encryption
 
 Revision ID: 2c577a8a01b7
 Revises: 2b89164aa9cd
diff --git a/migrations/versions/143_add_reply_to_message_id.py b/migrations/versions/143_add_reply_to_message_id.py
index 9c4e69370..add217cd4 100644
--- a/migrations/versions/143_add_reply_to_message_id.py
+++ b/migrations/versions/143_add_reply_to_message_id.py
@@ -25,7 +25,7 @@ def upgrade():
            WHERE table_name='message' AND referenced_table_name='message'
            AND constraint_schema=DATABASE()"""
     ).fetchone()[0]
-    conn.execute("ALTER TABLE message DROP FOREIGN KEY {}".format(constraint_name))
+    conn.execute(f"ALTER TABLE message DROP FOREIGN KEY {constraint_name}")
     conn.execute(
         "ALTER TABLE message CHANGE resolved_message_id reply_to_message_id INT(11)"
     )
@@ -43,7 +43,7 @@ def downgrade():
            WHERE table_name='message' AND referenced_table_name='message'
            AND constraint_schema=DATABASE()"""
     ).fetchone()[0]
-    conn.execute("ALTER TABLE message DROP FOREIGN KEY {}".format(constraint_name))
+    conn.execute(f"ALTER TABLE message DROP FOREIGN KEY {constraint_name}")
     conn.execute("ALTER TABLE message DROP FOREIGN KEY message_ibfk_3")
     conn.execute(
         "ALTER TABLE message CHANGE reply_to_message_id resolved_message_id INT(11)"
diff --git a/migrations/versions/150_add_polymorphic_events.py b/migrations/versions/150_add_polymorphic_events.py
index 5676c4a7d..471bf3689 100644
--- a/migrations/versions/150_add_polymorphic_events.py
+++ b/migrations/versions/150_add_polymorphic_events.py
@@ -79,7 +79,7 @@ def populate():
                 try:
                     raw_data = ast.literal_eval(e.raw_data)
                 except:
-                    print("Could not load raw data for event {}".format(e.id))
+                    print(f"Could not load raw data for event {e.id}")
                     continue
             e.recurrence = raw_data["recurrence"]
         db.commit()
@@ -98,7 +98,7 @@ def populate():
         try:
             db.execute(create)
         except Exception as e:
-            print("Couldn't insert RecurringEventOverrides: {}".format(e))
+            print(f"Couldn't insert RecurringEventOverrides: {e}")
             exit(2)
         print("done.")
 
@@ -113,7 +113,7 @@ def populate():
                 try:
                     raw_data = ast.literal_eval(e.raw_data)
                 except:
-                    print("Could not load raw data for event {}".format(e.id))
+                    print(f"Could not load raw data for event {e.id}")
                     continue
             rec_uid = raw_data.get("recurringEventId")
             if rec_uid:
@@ -133,7 +133,7 @@ def populate():
                     print(".", end=" ")
                     sys.stdout.flush()
         db.commit()
-        print("done. ({} modified)".format(c))
+        print(f"done. ({c} modified)")
 
         # Convert Event to RecurringEvent
         print("Updating types for RecurringEvent...", end=" ")
@@ -148,7 +148,7 @@ def populate():
         try:
             db.execute(create)
         except Exception as e:
-            print("Couldn't insert RecurringEvents: {}".format(e))
+            print(f"Couldn't insert RecurringEvents: {e}")
             exit(2)
         print("done.")
 
@@ -164,7 +164,7 @@ def populate():
                 try:
                     raw_data = ast.literal_eval(r.raw_data)
                 except:
-                    print("Could not load raw data for event {}".format(r.id))
+                    print(f"Could not load raw data for event {r.id}")
                     continue
             r.start_timezone = raw_data["start"].get("timeZone")
             # find any un-found overrides that didn't have masters earlier
@@ -175,7 +175,7 @@ def populate():
                 print(".", end=" ")
                 sys.stdout.flush()
         db.commit()
-        print("done. ({} modified)".format(c))
+        print(f"done. ({c} modified)")
 
         # Finally, convert all remaining Events to type='event'
         convert = """UPDATE event SET type='event' WHERE type IS NULL"""
diff --git a/migrations/versions/157_update_eas_schema.py b/migrations/versions/157_update_eas_schema.py
index 339a5961b..09a4d20f4 100644
--- a/migrations/versions/157_update_eas_schema.py
+++ b/migrations/versions/157_update_eas_schema.py
@@ -31,9 +31,7 @@ def upgrade():
            AND constraint_schema=DATABASE()"""
     ).fetchall()
     for (folder_fk,) in folder_fks:
-        conn.execute(
-            "ALTER TABLE easfoldersyncstatus DROP FOREIGN KEY {}".format(folder_fk)
-        )
+        conn.execute(f"ALTER TABLE easfoldersyncstatus DROP FOREIGN KEY {folder_fk}")
 
     # Drop folder_id foreign key constraint from easuid table
     folder_fks = conn.execute(
@@ -43,7 +41,7 @@ def upgrade():
            AND constraint_schema=DATABASE()"""
     ).fetchall()
     for (folder_fk,) in folder_fks:
-        conn.execute("ALTER TABLE easuid DROP FOREIGN KEY {}".format(folder_fk))
+        conn.execute(f"ALTER TABLE easuid DROP FOREIGN KEY {folder_fk}")
 
     # Add new index on easuid table
     conn.execute(
diff --git a/migrations/versions/160_split_actionlog.py b/migrations/versions/160_split_actionlog.py
index 8ce0f4413..5247cdf34 100644
--- a/migrations/versions/160_split_actionlog.py
+++ b/migrations/versions/160_split_actionlog.py
@@ -36,7 +36,7 @@ def upgrade():
             .options(contains_eager(ActionLog.namespace, Namespace.account))
         )
 
-        print("Updating {} action_log entries".format(q.count()))
+        print(f"Updating {q.count()} action_log entries")
 
         for a in q.all():
             a.type = "actionlog"
diff --git a/migrations/versions/164_add_decode_error_index.py b/migrations/versions/164_add_decode_error_index.py
index 86707ad47..a340d35cd 100644
--- a/migrations/versions/164_add_decode_error_index.py
+++ b/migrations/versions/164_add_decode_error_index.py
@@ -1,4 +1,4 @@
-"""add message.decode_error index """
+"""add message.decode_error index"""
 
 revision = "17dcbd7754e0"
 down_revision = "457164360472"
diff --git a/migrations/versions/171_update_easuid_schema_3.py b/migrations/versions/171_update_easuid_schema_3.py
index a968cb231..a43173696 100644
--- a/migrations/versions/171_update_easuid_schema_3.py
+++ b/migrations/versions/171_update_easuid_schema_3.py
@@ -36,7 +36,6 @@ class EASUid(Base):
             {"server_id": sa.func.concat(EASUid.fld_uid, ":", EASUid.msg_uid)},
             synchronize_session=False,
         )
-    pass
 
 
 def downgrade():
diff --git a/migrations/versions/175_fix_recurring_override_cascade.py b/migrations/versions/175_fix_recurring_override_cascade.py
index 80db66d0a..0f7bda8b2 100644
--- a/migrations/versions/175_fix_recurring_override_cascade.py
+++ b/migrations/versions/175_fix_recurring_override_cascade.py
@@ -28,7 +28,7 @@ def upgrade():
     ).fetchone()
 
     if fk_delete == "CASCADE":
-        print("Checked fk: {}. This migration is not needed, skipping.".format(fk_name))
+        print(f"Checked fk: {fk_name}. This migration is not needed, skipping.")
         return
 
     conn.execute(text("set @@lock_wait_timeout = 20;"))
diff --git a/migrations/versions/180_migrate_event_descriptions.py b/migrations/versions/180_migrate_event_descriptions.py
index 78ad9e294..0c1832e21 100644
--- a/migrations/versions/180_migrate_event_descriptions.py
+++ b/migrations/versions/180_migrate_event_descriptions.py
@@ -21,7 +21,7 @@ def upgrade():
             "UPDATE event SET _description=description "
             "WHERE _description IS NULL AND description IS NOT NULL LIMIT 100000"
         )
-        print("Updated {} rows".format(res.rowcount))
+        print(f"Updated {res.rowcount} rows")
         if res.rowcount == 0:
             return
 
diff --git a/migrations/versions/213_add_metadata_table.py b/migrations/versions/213_add_metadata_table.py
index a3e7e2022..02987cd5e 100644
--- a/migrations/versions/213_add_metadata_table.py
+++ b/migrations/versions/213_add_metadata_table.py
@@ -69,7 +69,7 @@ def upgrade():
 
     conn = op.get_bind()
     increment = (shard_id << 48) + 1
-    conn.execute("ALTER TABLE metadata AUTO_INCREMENT={}".format(increment))
+    conn.execute(f"ALTER TABLE metadata AUTO_INCREMENT={increment}")
 
 
 def downgrade():
diff --git a/migrations/versions/214_introduce_accounttransaction.py b/migrations/versions/214_introduce_accounttransaction.py
index 1268c0868..77daa3543 100644
--- a/migrations/versions/214_introduce_accounttransaction.py
+++ b/migrations/versions/214_introduce_accounttransaction.py
@@ -75,7 +75,7 @@ def upgrade():
 
     conn = op.get_bind()
     increment = (shard_id << 48) + 1
-    conn.execute("ALTER TABLE accounttransaction AUTO_INCREMENT={}".format(increment))
+    conn.execute(f"ALTER TABLE accounttransaction AUTO_INCREMENT={increment}")
 
 
 def downgrade():
diff --git a/migrations/versions/228_increase_gmailaccount_token_length.py b/migrations/versions/228_increase_gmailaccount_token_length.py
index 88ded41f7..014cf4ddd 100644
--- a/migrations/versions/228_increase_gmailaccount_token_length.py
+++ b/migrations/versions/228_increase_gmailaccount_token_length.py
@@ -17,10 +17,8 @@
 def upgrade():
     op.alter_column("gmailaccount", "g_id_token", type_=sa.String(length=2048))
     op.alter_column("gmailauthcredentials", "g_id_token", type_=sa.String(length=2048))
-    pass
 
 
 def downgrade():
     op.alter_column("gmailaccount", "g_id_token", type_=sa.String(length=1024))
     op.alter_column("gmailauthcredentials", "g_id_token", type_=sa.String(length=1024))
-    pass
diff --git a/migrations/versions/239_server_default_created_at.py b/migrations/versions/239_server_default_created_at.py
index 00a083af1..7f5c959dc 100644
--- a/migrations/versions/239_server_default_created_at.py
+++ b/migrations/versions/239_server_default_created_at.py
@@ -50,9 +50,7 @@ def upgrade():
     for table in TABLES:
         conn.execute(
             text(
-                "ALTER TABLE `{}` MODIFY COLUMN `created_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP".format(
-                    table
-                )
+                f"ALTER TABLE `{table}` MODIFY COLUMN `created_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP"
             )
         )
 
@@ -61,9 +59,5 @@ def downgrade():
     conn = op.get_bind()
     for table in TABLES:
         conn.execute(
-            text(
-                "ALTER TABLE `{}` MODIFY COLUMN `created_at` DATETIME NOT NULL".format(
-                    table
-                )
-            )
+            text(f"ALTER TABLE `{table}` MODIFY COLUMN `created_at` DATETIME NOT NULL")
         )
diff --git a/tests/api/base.py b/tests/api/base.py
index 69537f270..1638781d0 100644
--- a/tests/api/base.py
+++ b/tests/api/base.py
@@ -11,7 +11,6 @@ def new_api_client(db, namespace):
 
 
 class TestAPIClient:
-
     """Provide more convenient access to the API for testing purposes."""
 
     def __init__(self, test_client, default_namespace_public_id):
diff --git a/tests/api/test_drafts.py b/tests/api/test_drafts.py
index 0d48e4f13..526bd282a 100644
--- a/tests/api/test_drafts.py
+++ b/tests/api/test_drafts.py
@@ -1,5 +1,6 @@
 """Test local behavior for the drafts API. Doesn't test syncback or actual
-sending."""
+sending.
+"""
 import json
 import os
 from datetime import datetime
@@ -393,7 +394,8 @@ def test_update_to_nonexistent_draft(api_client):
 
 def test_contacts_updated(api_client):
     """Tests that draft-contact associations are properly created and
-    updated."""
+    updated.
+    """
     draft = {"to": [{"email": "alice@example.com"}, {"email": "bob@example.com"}]}
 
     r = api_client.post_data("/drafts", draft)
diff --git a/tests/api/test_filtering.py b/tests/api/test_filtering.py
index ba767fa92..ab0550599 100644
--- a/tests/api/test_filtering.py
+++ b/tests/api/test_filtering.py
@@ -285,7 +285,8 @@ def test_strict_argument_parsing(api_client):
 
 def test_distinct_results(api_client, db, default_namespace):
     """Test that limit and offset parameters work correctly when joining on
-    multiple matching messages per thread."""
+    multiple matching messages per thread.
+    """
     # Create a thread with multiple messages on it.
     first_thread = add_fake_thread(db.session, default_namespace.id)
     add_fake_message(
diff --git a/tests/api/test_messages.py b/tests/api/test_messages.py
index be08c5977..08d833b53 100644
--- a/tests/api/test_messages.py
+++ b/tests/api/test_messages.py
@@ -303,8 +303,8 @@ def test_message_label_updates(
     db, api_client, default_account, api_version, custom_label
 ):
     """Check that you can update a message (optimistically or not),
-    and that the update is queued in the ActionLog."""
-
+    and that the update is queued in the ActionLog.
+    """
     headers = dict()
     headers["Api-Version"] = api_version
 
diff --git a/tests/api/test_sending.py b/tests/api/test_sending.py
index 5cbef66eb..7a8a08560 100644
--- a/tests/api/test_sending.py
+++ b/tests/api/test_sending.py
@@ -993,9 +993,7 @@ def test_inline_html_image_send(patch_smtp, api_client, uploaded_file_ids):
         "/send",
         {
             "subject": "Inline image test",
-            "body": '<html><body><div></div><img src="cid:{}"><div></div></body></html>'.format(
-                file_id
-            ),
+            "body": f'<html><body><div></div><img src="cid:{file_id}"><div></div></body></html>',
             "file_ids": [file_id],
             "to": [{"name": "Foo Bar", "email": "foobar@nylas.com"}],
         },
diff --git a/tests/api/test_threads.py b/tests/api/test_threads.py
index 76b8beb61..e8dec0820 100644
--- a/tests/api/test_threads.py
+++ b/tests/api/test_threads.py
@@ -181,8 +181,8 @@ def test_thread_label_updates(
     db, api_client, default_account, api_version, custom_label
 ):
     """Check that you can update a message (optimistically or not),
-    and that the update is queued in the ActionLog."""
-
+    and that the update is queued in the ActionLog.
+    """
     headers = dict()
     headers["Api-Version"] = api_version
 
diff --git a/tests/api/test_views.py b/tests/api/test_views.py
index 8cac6d087..d5fa49029 100644
--- a/tests/api/test_views.py
+++ b/tests/api/test_views.py
@@ -34,7 +34,8 @@ def test_resource_views(
 ):
     """Exercises various tests for views, mostly related to
     filtering. Note: this only tests views, it assumes the
-    resources are working as expected."""
+    resources are working as expected.
+    """
     # Folders don't work with GMail accounts, need generic IMAP
     if resource_name == "folders":
         api_client = new_api_client(db, generic_account.namespace)
diff --git a/tests/conftest.py b/tests/conftest.py
index 6cf3d81bf..c10df74e2 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,4 +1,4 @@
-""" Fixtures don't go here; see util/base.py and friends. """
+"""Fixtures don't go here; see util/base.py and friends."""
 # Monkeypatch first, to prevent "AttributeError: 'module' object has no
 # attribute 'poll'" errors when tests import socket, then monkeypatch.
 from gevent import monkey
diff --git a/tests/contacts/test_process_mail.py b/tests/contacts/test_process_mail.py
index 6b4379072..40b40d521 100644
--- a/tests/contacts/test_process_mail.py
+++ b/tests/contacts/test_process_mail.py
@@ -1,5 +1,6 @@
 """Sanity-check our logic for updating contact data from message addressees
-during a sync."""
+during a sync.
+"""
 from inbox.models import Contact
 
 from tests.util.base import add_fake_message
diff --git a/tests/contacts/test_remote_sync.py b/tests/contacts/test_remote_sync.py
index 262638fbc..5ecfb0dce 100644
--- a/tests/contacts/test_remote_sync.py
+++ b/tests/contacts/test_remote_sync.py
@@ -91,7 +91,8 @@ def test_deletes(contacts_provider, contact_sync, db):
 )
 def test_auth_error_handling(contact_sync, default_account, db):
     """Test that the contact sync greenlet stops if account credentials are
-    invalid."""
+    invalid.
+    """
     # Give the default test account patently invalid OAuth credentials.
     default_account.refresh_token = "foo"
     db.session.commit()
diff --git a/tests/general/test_concurrency.py b/tests/general/test_concurrency.py
index bd66353fc..c60379f77 100644
--- a/tests/general/test_concurrency.py
+++ b/tests/general/test_concurrency.py
@@ -31,7 +31,6 @@ def __call__(self):
         time.sleep(self.delay)
         if self.call_count < self.max_executions:
             raise self.exc_type
-        return
 
 
 @pytest.mark.usefixtures("mock_gevent_sleep")
diff --git a/tests/general/test_html_parsing.py b/tests/general/test_html_parsing.py
index 542d63a33..282c6bf5d 100644
--- a/tests/general/test_html_parsing.py
+++ b/tests/general/test_html_parsing.py
@@ -25,7 +25,8 @@ def test_strip_tags():
 
 def test_preserve_refs():
     """Test that HTML character/entity references are preserved when we strip
-    tags."""
+    tags.
+    """
     text = "la philologie m&#x00e8;ne au pire"
     assert strip_tags(text) == "la philologie mène au pire"
 
diff --git a/tests/general/test_mutable_json_type.py b/tests/general/test_mutable_json_type.py
index bf6a4a4f2..c69d1ceb5 100644
--- a/tests/general/test_mutable_json_type.py
+++ b/tests/general/test_mutable_json_type.py
@@ -1,4 +1,4 @@
-""" Tests for our mutable JSON column type. """
+"""Tests for our mutable JSON column type."""
 
 from datetime import datetime
 
diff --git a/tests/general/test_relationships.py b/tests/general/test_relationships.py
index b961da86b..2cd115a58 100644
--- a/tests/general/test_relationships.py
+++ b/tests/general/test_relationships.py
@@ -8,8 +8,8 @@
 
 def test_category_delete(db, gmail_account):
     """Ensure that all associated MessageCategories are deleted
-    when a Category is deleted"""
-
+    when a Category is deleted
+    """
     api_client = new_api_client(db, gmail_account.namespace)
     po_data = api_client.post_data("/labels/", {"display_name": "Test_Label"})
     assert po_data.status_code == 200
@@ -51,8 +51,8 @@ def test_category_delete(db, gmail_account):
 
 def test_message_delete(db, gmail_account):
     """Ensure that all associated MessageCategories are deleted
-    when a Message is deleted"""
-
+    when a Message is deleted
+    """
     api_client = new_api_client(db, gmail_account.namespace)
 
     generic_thread = add_fake_thread(db.session, gmail_account.namespace.id)
@@ -91,8 +91,8 @@ def test_message_delete(db, gmail_account):
 
 def test_thread_delete(db, gmail_account):
     """Ensure that all associated Messages are deleted
-    when a Thread is deleted."""
-
+    when a Thread is deleted.
+    """
     generic_thread = add_fake_thread(db.session, gmail_account.namespace.id)
     generic_message = add_fake_message(
         db.session, gmail_account.namespace.id, generic_thread
diff --git a/tests/general/test_required_folders.py b/tests/general/test_required_folders.py
index 650b89b6d..069083c02 100644
--- a/tests/general/test_required_folders.py
+++ b/tests/general/test_required_folders.py
@@ -1,4 +1,4 @@
-""" Test that the All Mail folder is enabled for Gmail. """
+"""Test that the All Mail folder is enabled for Gmail."""
 import pytest
 
 from inbox.auth.google import GoogleAuthHandler
diff --git a/tests/general/test_thread_creation.py b/tests/general/test_thread_creation.py
index a9559ad7f..916d7475f 100644
--- a/tests/general/test_thread_creation.py
+++ b/tests/general/test_thread_creation.py
@@ -57,7 +57,8 @@ def test_generic_grouping(db, default_account):
 
 def test_threading_limit(db, folder_sync_engine, monkeypatch):
     """Test that custom threading doesn't produce arbitrarily long threads,
-    which eventually break things."""
+    which eventually break things.
+    """
     from inbox.models import Message, Thread
 
     # Shorten bound to make test faster
diff --git a/tests/imap/data.py b/tests/imap/data.py
index 7981d01aa..b1af22547 100644
--- a/tests/imap/data.py
+++ b/tests/imap/data.py
@@ -2,7 +2,8 @@
 well as a mock IMAPClient isntance that can be used to deterministically test
 aspects of IMAP sync.
 See https://hypothesis.readthedocs.org/en/latest/data.html for more information
-about how this works."""
+about how this works.
+"""
 import string
 
 import flanker
diff --git a/tests/imap/test_actions.py b/tests/imap/test_actions.py
index 5adf458a9..64a3f1627 100644
--- a/tests/imap/test_actions.py
+++ b/tests/imap/test_actions.py
@@ -83,9 +83,7 @@ def test_draft_updates(db, default_account, mock_imapclient):
         assert len(all_uids) == 1
         data = conn.uids(all_uids)[0]
         parsed = mime.from_string(data.body)
-        expected_message_id = "<{}-{}@mailer.nylas.com>".format(
-            draft.public_id, draft.version
-        )
+        expected_message_id = f"<{draft.public_id}-{draft.version}@mailer.nylas.com>"
         assert parsed.headers.get("Message-Id") == expected_message_id
 
         # We're testing the draft deletion with Gmail here. However,
diff --git a/tests/imap/test_crispin_client.py b/tests/imap/test_crispin_client.py
index d2cf38a21..e88f5a41c 100644
--- a/tests/imap/test_crispin_client.py
+++ b/tests/imap/test_crispin_client.py
@@ -640,7 +640,6 @@ def test_gmail_folders_no_flags(monkeypatch):
     """
     Tests that system folders (trash, inbox, sent) without flags can be labeled
     """
-
     folders = [
         ((b"\\HasNoChildren",), b"/", "INBOX"),
         ((b"\\Noselect", b"\\HasChildren"), b"/", "[Gmail]"),
@@ -679,7 +678,6 @@ def test_gmail_many_folders_one_role(monkeypatch, constants):
     i.e accounts with [Imap]/Trash, Trash, and [Gmail]/Trash
     should only have one folder with the role trash
     """
-
     # some duplitace folders where one has been flagged,
     # and neither have been flagged
     # in both cases, only one should come out flagged.
diff --git a/tests/imap/test_delete_handling.py b/tests/imap/test_delete_handling.py
index 67716baa7..d77c29043 100644
--- a/tests/imap/test_delete_handling.py
+++ b/tests/imap/test_delete_handling.py
@@ -62,7 +62,8 @@ def test_deleting_from_a_message_with_multiple_uids(
     db, default_account, message, thread
 ):
     """Check that deleting a imapuid from a message with
-    multiple uids doesn't mark the message for deletion."""
+    multiple uids doesn't mark the message for deletion.
+    """
     inbox_folder = Folder.find_or_create(db.session, default_account, "inbox", "inbox")
     sent_folder = Folder.find_or_create(db.session, default_account, "sent", "sent")
 
diff --git a/tests/scheduling/test_syncback_logic.py b/tests/scheduling/test_syncback_logic.py
index a3741a31e..a39bd057a 100644
--- a/tests/scheduling/test_syncback_logic.py
+++ b/tests/scheduling/test_syncback_logic.py
@@ -21,7 +21,7 @@ def purge_accounts_and_actions():
 
 @pytest.fixture
 def patched_enginemanager(monkeypatch):
-    engines = {k: None for k in range(0, 6)}
+    engines = {k: None for k in range(6)}
     monkeypatch.setattr("inbox.ignition.engine_manager.engines", engines)
     yield
     monkeypatch.undo()
diff --git a/tests/transactions/test_transaction_deletion.py b/tests/transactions/test_transaction_deletion.py
index b7008219e..c92ac9a4e 100644
--- a/tests/transactions/test_transaction_deletion.py
+++ b/tests/transactions/test_transaction_deletion.py
@@ -57,7 +57,6 @@ def transactions(self, clear_redis, now, db, default_namespace):
 
         Yields the newest transaction
         """
-
         # Transactions created less than 30 days ago should not be deleted
         t0 = create_transaction(db, now, default_namespace.id)
         create_transaction(db, now - timedelta(days=29), default_namespace.id)
@@ -88,8 +87,8 @@ def test_transaction_deletion_30_days(self, now, db, default_namespace):
         all_transactions = db.session.execute(query).scalar()
         date_query = (
             "SELECT count(id) FROM transaction WHERE created_at < "
-            "DATE_SUB({}, INTERVAL 30 day)"
-        ).format(format_datetime(now))
+            f"DATE_SUB({format_datetime(now)}, INTERVAL 30 day)"
+        )
         older_than_thirty_days = db.session.execute(date_query).scalar()
 
         # Delete all transactions older than 30 days
@@ -110,8 +109,8 @@ def test_transaction_deletion_one_day(
 
         date_query = (
             "SELECT count(id) FROM transaction WHERE created_at < "
-            "DATE_SUB({}, INTERVAL 1 day)"
-        ).format(format_datetime(now))
+            f"DATE_SUB({format_datetime(now)}, INTERVAL 1 day)"
+        )
         older_than_one_day = db.session.execute(date_query).scalar()
         # Delete all transactions older than 1 day
         purge_transactions(shard_id, days_ago=1, dry_run=False, now=now)
diff --git a/tests/util/base.py b/tests/util/base.py
index 8da8d2edd..5bde6a260 100644
--- a/tests/util/base.py
+++ b/tests/util/base.py
@@ -152,7 +152,7 @@ def default_account(db, config, redis_mock):
 
 @fixture(scope="function")
 def default_namespace(db, default_account):
-    yield default_account.namespace
+    return default_account.namespace
 
 
 @fixture
@@ -165,7 +165,7 @@ def outlook_account(db, config, redis_mock):
 
 @fixture
 def outlook_namespace(db, outlook_account):
-    yield outlook_account.namespace
+    return outlook_account.namespace
 
 
 @fixture(scope="function")
@@ -178,12 +178,12 @@ def default_accounts(db, config, redis_mock):
 
 @fixture(scope="function")
 def default_namespaces(db, default_accounts):
-    yield [account.namespace for account in default_accounts]
+    return [account.namespace for account in default_accounts]
 
 
 @fixture(scope="function")
 def generic_account(db):
-    yield add_generic_imap_account(db.session)
+    return add_generic_imap_account(db.session)
 
 
 @fixture(scope="function")