code: def start(self):
          
          if self.args.debug:
              self.app.run(port=self.args.port, debug=self.args.debug, host=self.args.interface)
          else:
              root = "http://%s:%s" % (self.args.interface, self.args.port)
              print("tornado web server running on " + root)
              self.shutdown_requested = False
              http_server = HTTPServer(WSGIContainer(self.app))
              http_server.listen(port=self.args.port, address=self.args.interface)
  
              signal.signal(signal.SIGINT, self.signal_handler)
              tornado.ioloop.PeriodicCallback(self.check_shutdown_flag, 500).start()
              tornado.ioloop.IOLoop.instance().start()
docs: Start the app