wait() if __name__ == '__main__': asyncio.run(main()) Configure your operating system or process manager to run this program to start the server. Please note that it may be necessary to increase the number the semaphore has been released once, by worker 0. The semaphore can be used as an async context manager: async def worker(worker_id): async with sem: print("Worker %d is working" % worker_id) await %d is done" % worker_id) For compatibility with older versions of Python, acquire is a context manager, so worker could also be written as: @gen.coroutine def worker(worker_id): with (yield sem.acquire()):

if __name__ == '__main__': asyncio.run(main()) Configure your operating system or process manager to run this program to start the server. Please note that it may be necessary to increase the number the semaphore has been released once, by worker 0. The semaphore can be used as an async context manager: async def worker(worker_id): async with sem: print("Worker %d is working" % worker_id) %d is done" % worker_id) For compatibility with older versions of Python, acquire is a context manager, so worker could also be written as: @gen.coroutine def worker(worker_id): with (yield sem