Update app.py

app.py

@@ -254,7 +254,7 @@ def save_chat_to_file(chat_history):
 
 def ask(user_message, chat_history):
     if not user_message:
-        return chat_history
+        return chat_history , chat_history, ""
 
     response = chatbot(user_message, chat_history)
     chat_history.append((user_message, response))