diff --git a/litellm/types/utils.py b/litellm/types/utils.py
index 5f31798da..4ae88a745 100644
--- a/litellm/types/utils.py
+++ b/litellm/types/utils.py
@@ -166,7 +166,9 @@ class FunctionCall(OpenAIObject):
 
 class Function(OpenAIObject):
     arguments: str
-    name: str
+    name: Optional[
+        str
+    ]  # can be None - openai e.g.: ChoiceDeltaToolCallFunction(arguments='{"', name=None), type=None)
 
     def __init__(
         self,
diff --git a/litellm/utils.py b/litellm/utils.py
index cf2c679a8..39ddc02ac 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -8126,7 +8126,7 @@ class CustomStreamWrapper:
 
             if chunk.startswith(self.complete_response):
                 # Remove last_sent_chunk only if it appears at the start of the new chunk
-                chunk = chunk[len(self.complete_response):]
+                chunk = chunk[len(self.complete_response) :]
 
             self.complete_response += chunk
             return chunk
@@ -9483,8 +9483,8 @@ class CustomStreamWrapper:
                             model_response.choices[0].delta = Delta(**_json_delta)
                         except Exception as e:
                             verbose_logger.error(
-                                "litellm.CustomStreamWrapper.chunk_creator(): Exception occured - {}".format(
-                                    str(e)
+                                "litellm.CustomStreamWrapper.chunk_creator(): Exception occured - {}\n{}".format(
+                                    str(e), traceback.format_exc()
                                 )
                             )
                             verbose_logger.debug(traceback.format_exc())
@@ -10124,7 +10124,7 @@ def mock_completion_streaming_obj(
     model_response, mock_response, model, n: Optional[int] = None
 ):
     for i in range(0, len(mock_response), 3):
-        completion_obj = Delta(role="assistant", content=mock_response[i: i + 3])
+        completion_obj = Delta(role="assistant", content=mock_response[i : i + 3])
         if n is None:
             model_response.choices[0].delta = completion_obj
         else:
@@ -10133,7 +10133,7 @@ def mock_completion_streaming_obj(
                 _streaming_choice = litellm.utils.StreamingChoices(
                     index=j,
                     delta=litellm.utils.Delta(
-                        role="assistant", content=mock_response[i: i + 3]
+                        role="assistant", content=mock_response[i : i + 3]
                     ),
                 )
                 _all_choices.append(_streaming_choice)
@@ -10145,7 +10145,7 @@ async def async_mock_completion_streaming_obj(
     model_response, mock_response, model, n: Optional[int] = None
 ):
     for i in range(0, len(mock_response), 3):
-        completion_obj = Delta(role="assistant", content=mock_response[i: i + 3])
+        completion_obj = Delta(role="assistant", content=mock_response[i : i + 3])
         if n is None:
             model_response.choices[0].delta = completion_obj
         else:
@@ -10154,7 +10154,7 @@ async def async_mock_completion_streaming_obj(
                 _streaming_choice = litellm.utils.StreamingChoices(
                     index=j,
                     delta=litellm.utils.Delta(
-                        role="assistant", content=mock_response[i: i + 3]
+                        role="assistant", content=mock_response[i : i + 3]
                     ),
                 )
                 _all_choices.append(_streaming_choice)