handle member: or maintainer: values being None

Author: mxmehl

gh_org_mgr/_gh_org.py

@@ -475,7 +475,13 @@ def _aggregate_lists(self, *lists: list[str | int]) -> list[str | int]:
         """Combine multiple lists into one while removing duplicates"""
         complete = []
         for single_list in lists:
-            complete.extend(single_list)
+            if single_list is not None:
+                complete.extend(single_list)
+            else:
+                logging.debug(
+                    "A list that we attempted to extend to another was None. "
+                    "This probably happened because a 'member:' or 'maintainer:' key was left empty"
+                )
 
         return list(set(complete))