diff --git a/chat/chat_server/db/db.py b/chat/chat_server/db/db.py
index ee564a1..83353b3 100644
--- a/chat/chat_server/db/db.py
+++ b/chat/chat_server/db/db.py
@@ -85,9 +85,8 @@ def password_correct(self, nick, password):
             log.err('DB: password_correct CALL SUCCESSFUL')
             if correct_password:
                 return correct_password[0][0] == password
-            else:
-                log.err('DB: password_correct CALL FAILURE: no such user in database')
-                raise failure.Failure(sqlite3.IntegrityError())
+            log.err('DB: password_correct CALL FAILURE: no such user in database')
+            raise failure.Failure(sqlite3.IntegrityError())
         except failure.Failure as f:
             log.err(f'DB: password_correct FAILURE: {f.getErrorMessage()}')
             raise
@@ -174,8 +173,7 @@ def add_notification(self, author, target, notification):
     @log_operation
     @defer.inlineCallbacks
     def get_notifications(self, user):
-        results = yield self._dbpool.runQuery(query.select_notifications, (user,))
-        return results
+        return (yield self._dbpool.runQuery(query.select_notifications, (user,)))
 
     @log_operation
     def delete_notifications(self, user):
diff --git a/chat/chat_server/dispatch/dispatcher.py b/chat/chat_server/dispatch/dispatcher.py
index b7b0177..0b11e82 100644
--- a/chat/chat_server/dispatch/dispatcher.py
+++ b/chat/chat_server/dispatch/dispatcher.py
@@ -45,10 +45,7 @@ def remove_peer(self, peer, nick=None):
             for c in self.channels.values():
                 c.unregister_user(nick)
         elif isinstance(peer, ChatServer):
-            nicks = []
-            for k, v in self.user2peer.items():
-                if v == peer:
-                    nicks.append(k)
+            nicks = [k for k, v in self.user2peer.items() if v == peer]
             self.server_peers.remove(peer)
             for n in nicks:
                 self.user2peer.pop(n, None)
diff --git a/chat/chat_server/peer/chat_client.py b/chat/chat_server/peer/chat_client.py
index 35706ff..28a09e8 100644
--- a/chat/chat_server/peer/chat_client.py
+++ b/chat/chat_server/peer/chat_client.py
@@ -490,7 +490,6 @@ def msg_JOIN(self, message):
             else:
                 if self.connected:
                     self.endpoint.no_channel(channel_name)
-            pass
         except failure.Failure:
             self.endpoint.internal_error('DB error, please try again.')
 
diff --git a/chat/client/gui_qt.py b/chat/client/gui_qt.py
index f24ebaf..219fc84 100644
--- a/chat/client/gui_qt.py
+++ b/chat/client/gui_qt.py
@@ -94,9 +94,8 @@ def __init__(self, app, parent=None):
     def send_message(self):
         message = self.ui.plainTextEdit.toPlainText()
         self.ui.textBrowser.append(message)
-        if message.strip(" ") != "":
-            if self.client:
-                self.client.handle_input(message.strip(" "))
+        if message.strip(" ") != "" and self.client:
+            self.client.handle_input(message.strip(" "))
         self.ui.plainTextEdit.clear()
 
     def quit_channel(self):
diff --git a/monitor/db.py b/monitor/db.py
index 0510a1a..b8422c4 100644
--- a/monitor/db.py
+++ b/monitor/db.py
@@ -6,8 +6,7 @@
 
 def connect_db():
     """Connects to the specific database."""
-    conn = sqlite3.connect(app.config['DATABASE'])
-    return conn
+    return sqlite3.connect(app.config['DATABASE'])
 
 
 def init_db():
diff --git a/monitor/monitor.py b/monitor/monitor.py
index af5c3a5..6950aeb 100644
--- a/monitor/monitor.py
+++ b/monitor/monitor.py
@@ -19,7 +19,7 @@ def extract_ratings(rows):
 
 # extracts all channels from records and returns list
 def extract_channels(rows):
-    return list(set([row[1] for row in rows]))
+    return list({row[1] for row in rows})
 
 
 @app.route('/', methods=['GET', 'POST'])
@@ -69,8 +69,8 @@ def history():
     ratings_list = extract_ratings(rows)
     channels_list = extract_channels(rows)
 
-    for i in range(0, len(ratings_list)):
-        for j in range(0, 6):
+    for i in range(len(ratings_list)):
+        for j in range(6):
 
             if ratings_list[i][j] < 0.5:
                 ratings_list[i][j] = 0
@@ -95,8 +95,8 @@ def channel(name):
     ratings_list = extract_ratings(rows)
     channels_list = [name]
 
-    for i in range(0, len(ratings_list)):
-        for j in range(0, 6):
+    for i in range(len(ratings_list)):
+        for j in range(6):
 
             if ratings_list[i][j] < 0.5:
                 ratings_list[i][j] = 0