diff --git a/litellm/caching/redis_cache.py b/litellm/caching/redis_cache.py
index ed0a22d78a7..263e1df2ee7 100644
--- a/litellm/caching/redis_cache.py
+++ b/litellm/caching/redis_cache.py
@@ -365,12 +365,12 @@ class RedisCache(BaseCache):
         self.redis_async_client = redis_async_client  # type: ignore
         return redis_async_client
 
-    def check_and_fix_namespace(self, key: Optional[str]) -> Optional[str]:
+    def check_and_fix_namespace(self, key: str) -> str:
         """
         Make sure each key starts with the given namespace
         """
         if key is None:
-            return key
+            return key  # type: ignore[return-value]
         if self.namespace is not None and not key.startswith(self.namespace):
             key = self.namespace + ":" + key