Sequence seq = getArgument(0).eval(docs, contextSequence, contextItem);
Sequence seq = getArgument(0).eval(contextSequence, contextItem);
	public Sequence eval(DocumentSet docs, Sequence contextSequence, Item contextItem)		throws XPathException {		Item item = contextItem;		if (getArgumentCount() > 0) {			Sequence seq = getArgument(0).eval(docs, contextSequence, contextItem);			if (seq.getLength() == 0)				return Sequence.EMPTY_SEQUENCE;			item = seq.itemAt(0);		}		if (!Type.subTypeOf(item.getType(), Type.NODE))			throw new XPathException("Context item is not a node; got " + Type.getTypeName(item.getType()));		if (item instanceof NodeProxy)			return new NodeProxy(((NodeProxy) item).doc, 1);		else			return (NodeImpl) ((NodeImpl) item).getOwnerDocument().getDocumentElement();	}