What did I do wrong?

Hello I’m trying to deploy my streamlit project using apache. When I restart apache, error pop up and I don’t know why.

I’m very beginner, so I thought followed instructions. But maybe inappropriate way.
I made st_app1 directory that contains hello.py


hello.py code is as below

print("Content-Type: text/plain;charset=utf-8 \n\n")

import streamlit as st

def print_hello():
    st.write('hello streamlit')

if __name__ == '__main__':

and 000-default.conf files content is also as below

<VirtualHost *:80>
	DocumentRoot /var/www/st_app1/hello.py
	RewriteEngine On
	RewriteCond %{HTTP:Upgrade} =websocket
	RewriteRule /(.*) ws://localhost:8501/$1 [P]
	RewriteCond %{HTTP:Upgrade} !=websocket
	RewriteRule /(.*) http://localhost:8501/$1 [P]
	ProxyPassReverse / http://localhost:8501

Can anyone point out what I did wrong?