Update app.py

app.py

@@ -32,7 +32,7 @@ with gr.Blocks() as demo:
     clear = gr.ClearButton([msg, chatbot])
 
     def user(user_message, history):
-        return gr.update(value="", interactive=False), history + [[user_message,None]]
+        return gr.update(value="", interactive=False), history + [[user_message,'']]
     def bot(history):
         # chat_history.append(message)  # Initialize chat history