docs: public static List<IntDependency> treeToDependencyList(Tree tree, Index<String> wordIndex, Index<String> tagIndex) {
      List<IntDependency> depList = new ArrayList<IntDependency>();
      treeToDependencyHelper(tree, depList, 0, wordIndex, tagIndex);
      if (DEBUG) {
        System.out.println("----------------------------");
        tree.pennPrint();
        System.out.println(depList);
      }
      return depList;
    }