def METHOD_NAME(self):
    code = textwrap.dedent(
        """
        import asyncio
        from tornado.netutil import bind_sockets
        from tornado.process import fork_processes, task_id
        from tornado.ioloop import IOLoop
        from tornado.tcpserver import TCPServer
        sockets = bind_sockets(0, address='127.0.0.1')
        fork_processes(3)
        async def post_fork_main():
            server = TCPServer()
            server.add_sockets(sockets)
        asyncio.run(post_fork_main())
        print(task_id(), end='')
    """
    )
    out, err = self.run_subproc(code)
    self.assertEqual("".join(sorted(out)), "012")
    self.assertEqual(err, "")