Update app.py

app.py

@@ -42,7 +42,7 @@ def launch_app(pipe, streamer):
         clear = gr.Button("Clear")
 
         def user(user_message, history):
-            return "", history + [[user_message, ""]]
+            return "", history + [[user_message, None]]
 
         def bot(history):
             prompt = chat_history(history)