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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def start(self):
 """Start the app"""

        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()