Better handling of missing imports in slack module

src/lvmopstools/slack.py

@@ -18,6 +18,13 @@
 from lvmopstools import config
 
 
+try:
+    from slack_sdk.errors import SlackApiError
+    from slack_sdk.web.async_client import AsyncWebClient
+except ImportError:
+    AsyncWebClient = None
+    SlackApiError = None
+
 __all__ = ["post_message", "get_user_id", "get_user_list"]
 
 
@@ -29,9 +36,7 @@
 def get_api_client(token: str | None = None):
     """Gets a Slack API client."""
 
-    try:
-        from slack_sdk.web.async_client import AsyncWebClient
-    except ImportError:
+    if AsyncWebClient is None:
         raise ImportError(
             "slack-sdk is not installed. Install the slack or all extras."
         )
@@ -96,11 +101,6 @@ async def post_message(
 
     """
 
-    try:
-        from slack_sdk.errors import SlackApiError
-    except ImportError:
-        SlackApiError = None
-
     if text is None and blocks is None:
         raise ValueError("Must specify either text or blocks.")
 
@@ -138,11 +138,6 @@ async def get_user_list():
 
     """
 
-    try:
-        from slack_sdk.errors import SlackApiError
-    except ImportError:
-        SlackApiError = None
-
     client = get_api_client()
     assert SlackApiError is not None