@abc.abstractmethod<EOL><INDENT>def get_resource_ids_by_groups(self, group_resource_ids):<DEDENT>
return<EOL>
Gets the list of ``Resource Ids`` corresponding to a list of ``Resource`` objects.

        :param group_resource_ids: list of resource ``Ids``
        :type group_resource_ids: ``osid.id.IdList``
        :return: list of resource ``Ids``
        :rtype: ``osid.id.IdList``
        :raise: ``NullArgument`` -- ``group_resource_ids`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

        *compliance: mandatory -- This method must be implemented.*