if(attributeValue == null)
{return null;}
final AtomicValue comparison = new AnyURIValue(attributeValue);
final DocumentSet documentSet = getPolicyDocuments(broker, true);
final NodeSet nodeSet = documentSet.docsToNodeSet();
final NativeValueIndex valueIndex = broker.getValueIndex();
final Sequence results = valueIndex.find(null, Constants.EQ, documentSet, null, NodeSet.ANCESTOR, attributeQName, comparison);
// Sequence results = index.findByQName(attributeQName, comparison, nodeSet);
//TODO : should we honour (# exist:force-index-use #) ?