def start(self):
    '\n        start monitor,\n        it will start a monitor thread.\n        '
    self.running_lock.acquire()
    self.running = True
    self.running_lock.release()
    self.fetch_thread.setDaemon(True)
    self.fetch_thread.start()
start monitor,
it will start a monitor thread.
def start(self):
    '\n        start monitor,\n        it will start a monitor thread.\n        '
    self.running_lock.acquire()
    self.running = True
    self.running_lock.release()
    self.fetch_thread.setDaemon(True)
    self.fetch_thread.start()