exceptions.py

import asyncio


def adapt(the_future):
    try:
        print("*** result before")
        the_future.result()
    except:
        print("*** exception before")
        the_future.exception()


f = asyncio.ensure_future(asyncio.sleep(10))
f.add_done_callback(adapt)
f.cancel()

asyncio.get_event_loop().run_until_complete(f)