code: @Override
      public NavigableSet<E> subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive)
      {
          int low = lowIndexOf(fromElement, fromInclusive);
          int high = highIndexOf(toElement, toInclusive);
          return new BinarySet(comparator, list.subList(low, high+1), false);
      }
docs: {@inheritDoc}
  @param fromElement
  @param fromInclusive
  @param toElement
  @param toInclusive
  @return