def get_relationship_query(self):
raise Unimplemented()<EOL>
Gets the query for relationship.

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

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