assert !(target instanceof ToplevelList) : "we have gone up too far!";
    public StepExecutionResult execute(StepExecutionResult state) throws CdlResolutionException {        CdlDocument owner = state.getNode().getOwner();        PropertyList target = owner.lookup(refroot);        if(target==null) {            throw new CdlResolutionException("Unknown reference root "+refroot.toString());        }        return state.next(target);    }