diff --git a/core/api_auth.py b/core/api_auth.py
index 730e659..cf964da 100644
--- a/core/api_auth.py
+++ b/core/api_auth.py
@@ -15,6 +15,7 @@ import json
 import hashlib
 import time
 import secrets
+import threading
 from typing import Dict, List, Optional
 from dataclasses import dataclass
 from functools import wraps