foo.py

import asyncio


async def sleep():
    print('start')
    try:
        await asyncio.sleep(100)
    except:
        print('canceld')

        
async def foo():
    task = asyncio.create_task(sleep())
    await asyncio.sleep(0)
    task.cancel()
    await asyncio.sleep(1)


loop = asyncio.get_event_loop()
loop.run_until_complete(foo())