newIter = new FilteredTripleIterator(iter, toPurge, false);
ByteArrayOutputStream out = new ByteArrayOutputStream();
newIter.toStream(out, RDFFormat.RDF_XML, false);
if (newIter.wasChangeMade()) {
XMLDatastreamProcessor newdsxml = dsxml.newVersion();
Datastream newds = newdsxml.getDatastream();
// TODO: setting of this on DatastreamAsXML
// TODO: wrap original datastream in handler class
newdsxml.setDSMDClass(dsxml.getDSMDClass());