is_shutting_down

        Determine if the parent is shutting down or this was
        triggered to shutdown

        :param shutdown_event: shutdown event

def is_shutting_down(
            self,
            shutdown_event):
        """is_shutting_down

        Determine if the parent is shutting down or this was
        triggered to shutdown

        :param shutdown_event: shutdown event
        """

        return bool(
            shutdown_event.is_set()
            or self.shutdown_now
            or self.run_once)