correlation upgrades

drb-c2-core/app/internal/vocabulary_learner.py

@@ -18,7 +18,7 @@ import asyncio
 import difflib
 import json
 import random
-from datetime import datetime, timezone
+from datetime import datetime, timezone, timedelta
 from typing import Optional
 from app.internal.logger import logger
 from app.internal import firestore as fstore