code: private static String getTabBasedOnLevel(int level, int indentSize) {
          StringBuilder sb = new StringBuilder();
          for(int i = 0; i < level; i ++) {
              for(int j = 0; j < indentSize; j++) {
                  sb.append(" ");
              }
          }
          return sb.toString();
      }
docs: calculate indent for formatting
  @return "   " string of empty spaces