@abc.abstractmethod<EOL><INDENT>def get_ancestor_vault_query(self):<DEDENT>
return<EOL>
Gets the query for a vault.

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

        :return: the vault query
        :rtype: ``osid.authorization.VaultQuery``
        :raise: ``Unimplemented`` -- ``supports_ancestor_vault_query()`` is ``false``

        *compliance: optional -- This method must be implemented if
        ``supports_ancestor_vault_query()`` is ``true``.*