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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_relation(self, related_model: type, relations: List[str]) -> Tuple[Optional[List[type]], Optional[type]]: """Transform the list of relation to list of class. :param related_mode: The model of the query. :type related_mode: type :param relations: The relation list get from the `_extract_relations`. :type relations: List[str] :return: Tuple with the list of relations (class) and the second element is the last relation class. :rtype: Tuple[Optional[List[type]], Optional[type]] """

        relations_list, last_relation = [], related_model
        for relation in relations:
            relationship = getattr(last_relation, relation, None)
            if relationship is None:
                return (None, None)
            last_relation = relationship.mapper.class_
            relations_list.append(last_relation)
        return (relations_list, last_relation)