diff --git a/fastapi/routing.py b/fastapi/routing.py
index 3abe0f2eb0..b72c4ea1ed 100644
--- a/fastapi/routing.py
+++ b/fastapi/routing.py
@@ -258,7 +258,11 @@ class EndpointContext(TypedDict, total=False):
 # Use a WeakKeyDictionary instead of a standard dict to prevent memory leaks
 # and cache collisions when endpoints are dynamically created and destroyed.
 # This cache will only be used for the fallback "slow path".
-_endpoint_context_cache: weakref.WeakKeyDictionary[Any, EndpointContext] = weakref.WeakKeyDictionary()
+_endpoint_context_cache: weakref.WeakKeyDictionary[Any, EndpointContext] = (
+    weakref.WeakKeyDictionary()
+)
+
+
 def _extract_endpoint_context(func: Any) -> EndpointContext:
     """Extract endpoint context with caching to avoid repeated file I/O."""