<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def close(self):
 """ Log disconnects. """

        time_spent = time.time() - self.time_start
        logger.debug(
            '<{}> Disconnect from [{}]:{}, time spent {:.3f} seconds'.format(
                self.id, self.client_ip, self.client_port, time_spent))
        return Milter.CONTINUE