code: private NodeSet<OWLClass> nodesToOwlClassNodeSet(Set<au.csiro.ontology.Node> nodes) {
          Set<Node<OWLClass>> temp = new HashSet<Node<OWLClass>>();
          for (au.csiro.ontology.Node n : nodes) {
              temp.add(nodeToOwlClassNode(n));
          }
          return new OWLClassNodeSet(temp);
      }
docs: Transforms a set of {@link ClassNode}s into a {@link NodeSet}.
  
  @param nodes
  @return