diff --git a/sync_ics2gcal/sync_calendar.py b/sync_ics2gcal/sync_calendar.py
index d65d9ba..e744687 100644
--- a/sync_ics2gcal/sync_calendar.py
+++ b/sync_ics2gcal/sync_calendar.py
@@ -27,7 +27,7 @@ def get_start_date(date: ConfigDate) -> datetime.datetime:
     return result
 
 
-def main() -> str:
+def main() -> None:
     config = load_config()
 
     if "logging" in config: