code: public static Node getNode(Model mo, int nodeID) throws JSONConverterException {
          Node n = new Node(nodeID);
          if (!mo.contains(n)) {
              throw new JSONConverterException("Undeclared node '" + nodeID + "'");
          }
          return n;
      }
docs: Get a node from its identifier.
  The node is already a part of the model
  
  @param mo the associated model to browse
  @param nodeID the node identifier
  @return the resulting node
  @throws JSONConverterException if there is no model, or if the node is unknown.