How I start my tornado app

app.py

def main(): # pragma: no cover
    tornado.options.parse_command_line()

    http_server = tornado.httpserver.HTTPServer(Application())
    print "Starting tornado on port", options.port
    http_server.listen(options.port)

    try:
        tornado.ioloop.IOLoop.instance().start()
    except KeyboardInterrupt:
        pass


if __name__ == "__main__":
    main()