Update app.py

app.py

@@ -131,8 +131,8 @@ def main():
     index = initialize_index()
     chat_engine = initialize_chat_engine(index)
 
-def chatbot_response(message, history):
-    return generate_response(message, history, chat_engine)
+    def chatbot_response(message, history=None):
+        return generate_response(message, history, chat_engine)
 
     gr.Interface(
         fn=chatbot_response,