fix team_roles

district/tasks.py

@@ -68,6 +68,9 @@ def import_people_from_team(
 ):
     from .models import DistrictOctopusPersonPage, DistrictPeoplePage
 
+    if team_roles is None:
+        team_roles = []
+
     lock_file_name = os.path.join(
         tempfile.gettempdir(),
         f"{people_parent_page_id}-{team_shortcut}-{','.join(team_roles)}.people-from-team-import-lock",