def decrement(self):
        if self.ref_count <= 0:
            raise Exception('Illegal operation: cannot decrement below zero')
        self.ref_count -= 1
        if self.ref_count == 0:
            self.on_zero()
dataset/ETHPy150Open XiaoMi/minos/supervisor/supervisor/socket_manager.py/ReferenceCounter.decrement/original