diff --git a/fastapi/utils.py b/fastapi/utils.py
index 8913d85b2dc40..17528210106b0 100644
--- a/fastapi/utils.py
+++ b/fastapi/utils.py
@@ -76,7 +76,7 @@ def create_cloned_field(
 ) -> ModelField:
     # _cloned_types has already cloned types, to support recursive models
     if cloned_types is None:
-        cloned_types = dict()
+        cloned_types = {}
     original_type = field.type_
     if is_dataclass(original_type) and hasattr(original_type, "__pydantic_model__"):
         original_type = original_type.__pydantic_model__