stopping_loop.py

import asyncio

async def say(what, when):
    await asyncio.sleep(when)
    print(what)

async def stop_after(loop, when):
    await asyncio.sleep(when)
    loop.stop()

loop = asyncio.get_event_loop()

loop.create_task(say("first hello", 2))
loop.create_task(say("second hello", 1))
loop.create_task(say("third hello", 4))
loop.create_task(stop_after(loop, 3))

loop.run_forever()
loop.close()