def get_ancestor_objective_bank_query(self):
raise errors.Unimplemented()<EOL>
Gets the query for an objective bank.

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

        return: (osid.learning.ObjectiveBankQuery) - the objective bank
                query
        raise:  Unimplemented -
                ``supports_ancestor_objective_bank_query()`` is
                ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_ancestor_calndar_query()`` is ``true``.*