<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def remove_root(self, id_):
 """Removes a root node. arg: id (osid.id.Id):
 the ``Id`` of the node raise: NotFound - ``id`` was not found or not in hierarchy raise: NullArgument - ``id`` is ``null`` raise: OperationFailed - unable to complete request raise: PermissionDenied - authorization failure *compliance: mandatory -- This method must be implemented.* """

        result = self._rls.get_relationships_by_genus_type_for_peers(self._phantom_root_id, id_, self._relationship_type)
        if not bool(result.available()):
            raise errors.NotFound()
        self._ras.delete_relationship(result.get_next_relationship().get_id())
        self._adopt_orphans(id_)