Update app.py

app.py

@@ -1,3 +1,4 @@
+from datetime import datetime, timedelta
 from functools import partial
 from os import environ
 from typing import Callable, Coroutine
@@ -8,7 +9,6 @@ from fastapi.responses import HTMLResponse
 from fastapi.responses import StreamingResponse
 from httpx import AsyncClient, RequestError, Timeout
 from starlette.types import Receive, Scope, Send
-from datetime import datetime, timedelta
 
 API_KEYS = [line for line in environ['API_KEYS'].strip().split('\n') if line and line.startswith('sk-')]
 COMPLETIONS_URL = 'https://openrouter.ai/api/v1/chat/completions'
@@ -19,12 +19,12 @@ class Cache:
     def __init__(self, expire: timedelta):
         self.expire = expire
         self.cache = {}
-        self.timestamp = datetime.utcnow()
+        self.timestamp = datetime.now()
 
     async def get(self, key):
-        if datetime.utcnow() - self.timestamp > self.expire:
+        if datetime.now() - self.timestamp > self.expire:
             self.cache.clear()
-            self.timestamp = datetime.utcnow()
+            self.timestamp = datetime.now()
         return self.cache.get(key)
 
     async def set(self, key, value):