timer.py 文件源码

def __init__(
            self,
            callback,
            timer=TIMER,
            interval=INTERVAL_SECONDS,
            timer_signal=TIMER_SIGNAL):

        assert callable(callback), 'callback must be callable'

        signal.signal(timer_signal, self.callback)
        signal.setitimer(timer, interval, interval)

        oldtimer, oldaction = None, None  # cheating for now
        self.oldaction = oldaction
        self.oldtimer = oldtimer
        self._callback = callback