/**
  * Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed
  * to work.
  *
  * @param depth The depth to indent the sub-nodes
  */
 public void printSubNodes(int depth) {
   for (int index = 0; index < size(); index++) {
     debugPrint(formatNodeString("[" + index + "]:", depth));
     N elt = get(index);
     elt.treePrint(depth);
   }
 }