new_contents: from flask import Flask
  app = Flask(__name__)
  app.config['DEBUG'] = True
  
  # Note: We don't need to call run() since our application is embedded within
  # the App Engine WSGI application server.
  
  
  @app.route('/')
  def hello():
      """Return a friendly HTTP greeting."""
      return 'Hello World!'
  
  
  @app.errorhandler(404)
  def page_not_found(e):
      """Return a custom 404 error."""
      return 'Sorry, nothing at this URL.', 404
  
subject: Create min.py