    def on_hold(self):
        """bool: If True, the scheduler won't execute new tasks
        till this is set False. Useful to halt task execution in
        a controller task."""
        return not self._flag_enabled.is_set()
bool: If True, the scheduler won't execute new tasks
till this is set False. Useful to halt task execution in
a controller task.
rocketry/core/schedule.py