diff --git a/docs_src/query_params_str_validations/tutorial006d_an_py310.py b/docs_src/query_params_str_validations/tutorial006d_an_py310.py
index 9a9d082bf..94af45722 100644
--- a/docs_src/query_params_str_validations/tutorial006d_an_py310.py
+++ b/docs_src/query_params_str_validations/tutorial006d_an_py310.py
@@ -14,6 +14,6 @@ def nullable_str(val: str) -> Union[str, None]:
 
 @app.get("/items/")
 async def read_items(
-    q: Annotated[Optional[str], Query(min_length=3), BeforeValidator(nullable_str)]
+    q: Annotated[Optional[str], Query(min_length=3), BeforeValidator(nullable_str)],
 ):
     return {"q": q}