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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def do_expire(self):
 """ Expire objects assuming now == time """

        # Deep copy to avoid RuntimeError: dictionary changed size during iteration
        _timeouts = deepcopy(self.timeouts)
        for key, value in _timeouts.items():
            if value - self.clock.now() < timedelta(0):
                del self.timeouts[key]
                # removing the expired key
                if key in self.redis:
                    self.redis.pop(key, None)