import asyncio
from asyncio.unix_events import SelectorEventLoop

class MyLoop(SelectorEventLoop):
    def __init__(self, *args, **kw):
        self.calls = 0
        SelectorEventLoop.__init__(self, *args, **kw)

    def _run_once(self):
        self.calls += 1
        SelectorEventLoop._run_once(self)

@asyncio.coroutine
def compute(x, y):
    print("Compute %s + %s ..." % (x, y))
    yield from asyncio.sleep(1.0)
    return x + y

@asyncio.coroutine
def wrapper(coro):
    print("wrap", coro)
    yield from coro

@asyncio.coroutine
def print_sum(x, y):
    result = yield from wrapper(compute(x, y))
    print("%s + %s = %s" % (x, y, result))

loop = MyLoop()
asyncio.set_event_loop(loop)
loop.run_until_complete(print_sum(1, 2))

print(loop.calls, "calls to _run_once")