runTimeTypeError("reference", "node-set");
runTimeTypeError("reference", obj.getClass().getName());
    public static NodeIterator referenceToNodeSet(Object obj) {	try {	    // Convert var/param -> node	    if (obj instanceof Node) {		return(new SingletonIterator(((Node)obj).node));	    }	    // Convert var/param -> node-set	    else if (obj instanceof NodeIterator) {		return(((NodeIterator)obj).cloneIterator());	    }	    // Convert var/param -> result-tree fragment	    else if (obj instanceof DOM) {		DOM dom = (DOM)obj;		return(dom.getIterator());	    }	    else {		runTimeTypeError("reference", "node-set");		return null;	    }	}	catch (ClassCastException e) {	    runTimeTypeError("reference", "node-set");	    return null;	}    }