diff --git a/src/llamafactory/data/converter.py b/src/llamafactory/data/converter.py
index 7ec6f12be..ad49deded 100644
--- a/src/llamafactory/data/converter.py
+++ b/src/llamafactory/data/converter.py
@@ -257,8 +257,8 @@ class OpenAIDatasetConverter(DatasetConverter):
             content = message[self.dataset_attr.content_tag]
 
             if role in [self.dataset_attr.assistant_tag, self.dataset_attr.function_tag]:
-                if "tool_calls" in message and len(message["tool_calls"]) > 0:
-                    tool_calls_list = [tool["function"] for tool in message["tool_calls"]]
+                if tool_calls := message.get("tool_calls"):
+                    tool_calls_list = [tool["function"] for tool in tool_calls]
                     content = json.dumps(tool_calls_list, ensure_ascii=False)
                     role = self.dataset_attr.function_tag