@utilities.arguments_not_none<EOL><INDENT>def is_descendant(self, id_, descendant_id):<DEDENT>
raise errors.Unimplemented()<EOL>
Tests if a node is a descendant of another.

        arg:    id (osid.id.Id): the ``Id`` to query
        arg:    descendant_id (osid.id.Id): the ``Id`` of a descendant
        return: (boolean) - ``true`` if this ``descendant_id`` is a
                child of the ``Id,``  ``false`` otherwise
        raise:  NotFound - ``id`` is not found
        raise:  NullArgument - ``id`` or ``descendant`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*
        *implementation notes*: If not found return ``false``.