@Override
 public void visit(OWLDataUnionOf node) {
   handleObject(node);
   for (OWLDataRange rng : node.getOperands()) {
     rng.accept(this);
   }
 }
 public void visit(OWLDataUnionOf node) {
   for (OWLDataRange dr : node.getOperands()) {
     dr.accept(this);
   }
 }