old_contents: #!/usr/bin/env python
  
  from flask import Flask
  app = Flask(__name__)
  
  @app.route('/hi')
  def hello_world():
      return 'Hello World!'
  
  if __name__ == '__main__':
      app.run(host='0.0.0.0', port='5000')
  
new_contents: #!/usr/bin/env python
  
  from flask import Flask
  app = Flask(__name__)
  
  @app.route('/hi')
  def hello_world():
      return 'Hello World!'
  
  if __name__ == '__main__':
      app.run(host='0.0.0.0', port=5000)
  
subject: fix typo in flask code