Gradio-NameError: name 'process_user_input' is not defined

Beginners
9

It started up when I did this.

import gradio as gr

def process_user_input(message):
    return message

def main_pipeline(message, history):
    response = process_user_input(message)
    return response

chat_interface = gr.ChatInterface(main_pipeline, type="messages")

if __name__ == "__main__":
    chat_interface.launch()

BTW, ``` ``` is good but ```py ``` is more cool for Python code.