code: def __get_timemachine(self):
          
          if not self.__timemachine:
              self.__timemachine = TimeMachine(
                  self.object_uid,
                  step = self.id,
              )
  
          return self.__timemachine.at(self.id)
docs: Return a TimeMachine for the object on which this action was 
          performed and at the time of this action.