diff --git a/litellm/caching/caching.py b/litellm/caching/caching.py
index faf660dfe1f..9299c875ca7 100644
--- a/litellm/caching/caching.py
+++ b/litellm/caching/caching.py
@@ -658,7 +658,7 @@ class Cache:
         )
         namespace: Final[str | None] = (
             ":".join(
-                value
+                cast(str, value)
                 for value in namespace_parts
                 if isinstance(value, str) and value
             )