coroutine_fun

import asyncio
import itertools
import sys


@asyncio.coroutine
def spin(msg):
    write, flush = sys.stdout.write, sys.stdout.flush
    for char in itertools.cycle('/-\\|'):
        status = char + ' ' + msg
        write(status)
        flush()
        write('\x08' * len(status))
        try:
            yield from asyncio.sleep(.1)
        except asyncio.CancelledError:
            break
    write(' ' * len(status) + '\x08' * len(status))
    
@asyncio.coroutine
def slow_function():
    yield from asyncio.sleep(8)
    return 42

@asyncio.coroutine
def supervisor():
    spinner = asyncio.ensure_future(spin('thinking!'))
    print('spinner object:', spinner)
    result = yield from slow_function()
    spinner.cancel()
    return result

loop = asyncio.get_event_loop()
result = loop.run_until_complete(supervisor())
loop.close()
print('Answer:', result)