Attach a model instance to the parent models.

        :param model: The model instance to attach
        :type model: Model

        :rtype: Model

def save(self, model):
        """
        Attach a model instance to the parent models.

        :param model: The model instance to attach
        :type model: Model

        :rtype: Model
        """
        model.set_attribute(self.get_plain_foreign_key(), self.get_parent_key())

        if model.save():
            return model

        return False