}
    final int off = lowerIndex;
    final int len = upperIndex - lowerIndex;
    ImmutableList<Range<K>> subRanges =
        new ImmutableList<Range<K>>() {
          @Override
          public int size() {
            return len;
          }

          @Override
          public Range<K> get(int index) {
            checkElementIndex(index, len);
            if (index == 0 || index == len - 1) {