diff --git a/litellm/llms/vertex_ai/gemini/transformation.py b/litellm/llms/vertex_ai/gemini/transformation.py
index 65cdddd6c01..be5fec2c224 100644
--- a/litellm/llms/vertex_ai/gemini/transformation.py
+++ b/litellm/llms/vertex_ai/gemini/transformation.py
@@ -991,9 +991,8 @@ def _gemini_convert_messages_with_history(  # noqa: PLR0915
                     # copy it to parallel function calls missing thoughtSignature.
                     turn_thought_signature = None
                     for existing_part in assistant_content:
-                        if (
-                            isinstance(existing_part, dict)
-                            and existing_part.get("thoughtSignature")
+                        if isinstance(existing_part, dict) and existing_part.get(
+                            "thoughtSignature"
                         ):
                             turn_thought_signature = existing_part.get(
                                 "thoughtSignature"
diff --git a/tests/test_litellm/llms/vertex_ai/gemini/test_vertex_ai_gemini_transformation.py b/tests/test_litellm/llms/vertex_ai/gemini/test_vertex_ai_gemini_transformation.py
index 68de50d3b0c..3c3e05390eb 100644
--- a/tests/test_litellm/llms/vertex_ai/gemini/test_vertex_ai_gemini_transformation.py
+++ b/tests/test_litellm/llms/vertex_ai/gemini/test_vertex_ai_gemini_transformation.py
@@ -563,7 +563,9 @@ def test_parallel_tool_calls_copy_thought_signature_from_thinking_block():
     assert len(contents) == 1
     model_parts = contents[0]["parts"]
     function_parts = [
-        p for p in model_parts if p.get("functionCall") is not None or p.get("function_call") is not None
+        p
+        for p in model_parts
+        if p.get("functionCall") is not None or p.get("function_call") is not None
     ]
     assert len(function_parts) == 2
     assert all(p.get("thoughtSignature") == "sig-turn-123" for p in function_parts)
@@ -613,9 +615,7 @@ def test_parallel_tool_calls_copy_thought_signature_from_text_thinking_block():
         if p.get("functionCall") is not None or p.get("function_call") is not None
     ]
     assert len(function_parts) == 2
-    assert all(
-        p.get("thoughtSignature") == "sig-text-thinking" for p in function_parts
-    )
+    assert all(p.get("thoughtSignature") == "sig-text-thinking" for p in function_parts)
 
 
 def test_thought_signature_with_function_call_mode():
diff --git a/tests/test_litellm/llms/vertex_ai/test_vertex.py b/tests/test_litellm/llms/vertex_ai/test_vertex.py
index be0e59e8b7d..a3dee0376f3 100644
--- a/tests/test_litellm/llms/vertex_ai/test_vertex.py
+++ b/tests/test_litellm/llms/vertex_ai/test_vertex.py
@@ -393,8 +393,8 @@ def test_multiple_function_call():
                     "role": "model",
                     "parts": [
                         {"text": "test"},
-                        {"function_call": {"name": "test", "args": {"arg": "test"}}},
-                        {"function_call": {"name": "test2", "args": {"arg": "test2"}}},
+                        {"functionCall": {"name": "test", "args": {"arg": "test"}}},
+                        {"functionCall": {"name": "test2", "args": {"arg": "test2"}}},
                     ],
                 },
                 {
@@ -502,8 +502,8 @@ def test_multiple_function_call_changed_text_pos():
                 "role": "model",
                 "parts": [
                     {"text": "test"},
-                    {"function_call": {"name": "test", "args": {"arg": "test"}}},
-                    {"function_call": {"name": "test2", "args": {"arg": "test2"}}},
+                    {"functionCall": {"name": "test", "args": {"arg": "test"}}},
+                    {"functionCall": {"name": "test2", "args": {"arg": "test2"}}},
                 ],
             },
             {
@@ -1282,7 +1282,6 @@ def test_process_gemini_media():
     assert base64_result["inline_data"]["data"] == "/9j/4AAQSkZJRg..."
 
 
-
 def test_get_image_mime_type_from_url():
     """Test the _get_image_mime_type_from_url function for different image URLs"""
     from litellm.llms.vertex_ai.gemini.transformation import (