Update mineru/utils/llm_aided.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

mineru/utils/llm_aided.py

@@ -89,7 +89,7 @@ Corrected title list:
             )
             content_pieces = []
             for chunk in completion:
-                if chunk.choices:
+                if chunk.choices and chunk.choices[0].delta.content is not None:
                     content_pieces.append(chunk.choices[0].delta.content)
             content = "".join(content_pieces).strip()
             # logger.info(f"Title completion: {content}")