old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  import os
  
  import tornado.ioloop
  import tornado.web
  from tornado.web import url
  from tornado.options import parse_command_line
  
  import settings
  
  
  class TornadoApp(tornado.web.Application):
      def __init__(self):
          handlers = [
              # url(r'/', MainHandler),
          ]
          app_settings = settings.init_settings()
          super().__init__(handlers, **app_settings)
  
  
  if __name__ == '__main__':
      parse_command_line()
      TornadoApp().listen(int(os.environ['PORT']))
      tornado.ioloop.IOLoop.instance().start()
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  import os
  
  import tornado.ioloop
  import tornado.web
  from tornado.web import url
  from tornado.options import parse_command_line
  
  import settings
  
  
  class TornadoApp(tornado.web.Application):
      def __init__(self):
          handlers = [
              # url(r'/', MainHandler),
          ]
          app_settings = settings.init()
          super().__init__(handlers, **app_settings)
  
  
  if __name__ == '__main__':
      parse_command_line()
      TornadoApp().listen(int(os.environ['PORT']))
      tornado.ioloop.IOLoop.instance().start()
  
subject: Update main.py