diff --git a/libs/standard-tests/langchain_standard_tests/unit_tests/chat_models.py b/libs/standard-tests/langchain_standard_tests/unit_tests/chat_models.py
index b7007a196ba..3ffca1bb53b 100644
--- a/libs/standard-tests/langchain_standard_tests/unit_tests/chat_models.py
+++ b/libs/standard-tests/langchain_standard_tests/unit_tests/chat_models.py
@@ -29,7 +29,8 @@ def my_adder(a: int, b: int) -> int:
 class ChatModelTests(ABC):
     @property
     @abstractmethod
-    def chat_model_class(self) -> Type[BaseChatModel]: ...
+    def chat_model_class(self) -> Type[BaseChatModel]:
+        ...
 
     @property
     def chat_model_params(self) -> dict: