old_contents: from flask import Flask, render_template
  import os
  
  
  app = Flask(__name__)
  
  @app.route('/')
  def webprint():
      return(render_template('index.html'))
  
  if __name__ == "__main__":
      port = int(os.environ.get('PORT', 5000))
      app.run(host='0.0.0.0', port=port)
  
new_contents: from flask import Flask, render_template
  import os
  
  
  app = Flask(__name__)
  
  @app.route('/')
  def webprint():
      return 'Hello world!'
  
  if __name__ == "__main__":
      port = int(os.environ.get('PORT', 5000))
      app.run(host='0.0.0.0', port=port)
  
subject: Return text message on /