MyPy のエラー対応

update_db.py

@@ -91,13 +91,11 @@ def update_tables (
 ) -> None:
     video_ids: list[int] = []
     for datum in api_data:
-        tag_names = datum['tags'].split ()
+        tag_names: list[str] = datum['tags'].split ()
         video = VideoDto (code          = datum['contentId'],
                           title         = datum['title'],
-                          description   = datum['description'],
+                          description   = datum['description'] or '',
                           uploaded_at   = datetime.fromisoformat (datum['startTime']))
-        if video.description is None:
-            video.description = ''
         video_dao.upsert (video, False)
         if video.id_ is not None:
             video_ids.append (video.id_)