fix: Only include extra_headers in send_completion if not None

aider/sendchat.py

@@ -88,13 +88,16 @@ def send_completion(
 @lazy_litellm_retry_decorator
 def simple_send_with_retries(model_name, messages, extra_headers=None):
     try:
-        _hash, response = send_completion(
+        kwargs = {
-            model_name=model_name,
+            "model_name": model_name,
-            messages=messages,
+            "messages": messages,
-            functions=None,
+            "functions": None,
-            stream=False,
+            "stream": False,
-            extra_headers=extra_headers,
+        }
-        )
+        if extra_headers is not None:
+            kwargs["extra_headers"] = extra_headers
+        
+        _hash, response = send_completion(**kwargs)
         return response.choices[0].message.content
     except (AttributeError, litellm.exceptions.BadRequestError):
         return