Get all of the IDs for the related models.

        :rtype: list

def get_related_ids(self):
        """
        Get all of the IDs for the related models.

        :rtype: list
        """
        related = self.get_related()

        full_key = related.get_qualified_key_name()

        return self.get_query().select(full_key).lists(related.get_key_name())