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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 __get_timemachine(self):
 """Return a TimeMachine for the object on which this action was performed and at the time of this action."""

        if not self.__timemachine:
            self.__timemachine = TimeMachine(
                self.object_uid,
                step = self.id,
            )

        return self.__timemachine.at(self.id)