throw new XPathException("intersect operand is not a node sequence");
throw new XPathException("except operand is not a node sequence");
	public Sequence eval(Sequence contextSequence, Item contextItem)		throws XPathException {		Sequence lval = left.eval(contextSequence, contextItem);		Sequence rval = right.eval(contextSequence, contextItem);		if(lval.getItemType() != Type.NODE || rval.getItemType() != Type.NODE)			throw new XPathException("intersect operand is not a node sequence");		NodeSet result = ((NodeSet)lval).intersection((NodeSet)rval);		return result;	}