public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
Sequence result = new ValueSequence();
if (use_attribute_sets != null) {
result.addAll(
((XSLContext)context).getXSLStylesheet()
.attributeSet(use_attribute_sets, contextSequence, contextItem)
);
} else if (delay_use_attribute_sets != null) {
return getXSLContext().getXSLStylesheet().attributeSet(delay_use_attribute_sets, contextSequence, contextItem);