import threading


class Timer(object):
    def __init__(self, func, args=(), kwargs=None, interval=20):
        if kwargs is None:
            kwargs = {}
        self._args = args
        self._kwargs = kwargs
        self.active = True
        self.__flag = threading.Event()
        self._func = func
        self.interval = interval

    def __timer(self):
        while self.active:
            self._func(*self._args, **self._kwargs)
            self.__flag.wait(self.interval)

    def start(self):
        self.__timer()

    def stop(self):
        self.active = False
        self.__flag.set()