Update app.py

app.py

@@ -145,7 +145,7 @@ with gr.Blocks() as demo:
 
 
     def user(user_message, history):
-        return "", history + [[user_message, '']]
+        return "", history + [[user_message, None]]
 
 
     def bot(history, max_new_tokens, temperature, top_p, system_prompt):
@@ -203,7 +203,8 @@ with gr.Blocks() as demo:
     
                         delta = json_response["result"]["fragment"]["data"]["text"]
                        
-
+                        if history[-1][1] is None:
+                            history[-1][1] = ''
                         history[-1][1] += delta
                         yield history