def get_descendant_family_query(self):
raise errors.Unimplemented()<EOL>
Gets the query interface for a family.

        Multiple retrievals produce a nested ``OR`` term.

        return: (osid.relationship.FamilyQuery) - the family query
        raise:  Unimplemented - ``supports_descendant_family_query()``
                is ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_descendant_family_query()`` is ``true``.*