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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 register_clean(self, entity_class, entity):
 """ Registers the given entity for the given class as CLEAN. :returns: Cloned entity. """

        EntityState.manage(entity, self)
        EntityState.get_state(entity).status = ENTITY_STATUS.CLEAN
        self.__entity_set_map[entity_class].add(entity)