update oai

qwen_server/assistant_server.py

@@ -100,7 +100,8 @@ def bot(history):
         response = agent.run(user_request=history[-1][0], ref_doc=_ref)
 
         for chunk in response:
-            history[-1][1] += chunk
+            if chunk is not None:
+                history[-1][1] += chunk
             yield history
 
         # save history