如何定期使用asyncio执行功能？

对于3.5以下的Python版本：

import asyncio@asyncio.coroutinedef periodic():    while True:        print('periodic')        yield from asyncio.sleep(1)def stop():    task.cancel()loop = asyncio.get_event_loop()loop.call_later(5, stop)task = loop.create_task(periodic())try:    loop.run_until_complete(task)except asyncio.CancelledError:    pass

对于Python 3.5及更高版本：

import asyncioasync def periodic():    while True:        print('periodic')        await asyncio.sleep(1)def stop():    task.cancel()loop = asyncio.get_event_loop()loop.call_later(5, stop)task = loop.create_task(periodic())try:    loop.run_until_complete(task)except asyncio.CancelledError:    pass