def sorted_window_ids(order='mru'):
        """
        Returns window ids orderd by criteria
        default is mru (most recently used)

        CommandLine:
            xprop -root | grep "^_NET_CLIENT_LIST_STACKING" | tr "," " "
            python -m utool.util_ubuntu XCtrl.sorted_window_ids
        """
        import utool as ut
        if order in ['mru', 'lru']:
            cmdkw = dict(verbose=False, quiet=True, silence=True)
            winid_order_str = ut.cmd(
                'xprop -root | grep "^_NET_CLIENT_LIST_STACKING"', **cmdkw)[0]
            winid_order = winid_order_str.split('#')[1].strip().split(', ')[::-1]
            winid_order = [int(h, 16) for h in winid_order]
            if order == 'lru':
                winid_order = winid_order[::-1]
        else:
            raise NotImplementedError(order)
        return winid_order