diff --git a/libs/partners/openai/langchain_openai/chat_models/base.py b/libs/partners/openai/langchain_openai/chat_models/base.py
index be4c1ca19e7..4dfd231a040 100644
--- a/libs/partners/openai/langchain_openai/chat_models/base.py
+++ b/libs/partners/openai/langchain_openai/chat_models/base.py
@@ -2197,7 +2197,8 @@ def _resize(width: int, height: int) -> Tuple[int, int]:
 
 def _update_schema_with_optional_fields(input_dict: dict) -> dict:
     """Convert optional fields to required fields allowing 'null' type."""
-    def _update_properties(schema: dict):
+
+    def _update_properties(schema: dict) -> None:
         if schema.get("type") != "object":
             return
 
diff --git a/libs/partners/openai/tests/unit_tests/chat_models/test_base.py b/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
index d588cc82dd8..4494a1bccf1 100644
--- a/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
+++ b/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
@@ -851,17 +851,19 @@ def test__convert_to_openai_response_format() -> None:
     assert expected == actual
 
     ## JSON Schema
-    class Entity(BaseModel):
+    class EntityModel(BaseModel):
         """Extracted entity."""
 
         animal: str = Field(description="The animal")
         color: Optional[str] = Field(default=None, description="The color")
 
-    actual = _convert_to_openai_response_format(Entity.model_json_schema(), strict=True)
+    actual = _convert_to_openai_response_format(
+        EntityModel.model_json_schema(), strict=True
+    )
     expected = {
         "type": "json_schema",
         "json_schema": {
-            "name": "Entity",
+            "name": "EntityModel",
             "description": "Extracted entity.",
             "strict": True,
             "schema": {