public static <C extends Comparable> ImmutableRangeSet<C> copyOf(RangeSet<C> rangeSet) {
    checkNotNull(rangeSet);
    if (rangeSet.isEmpty()) {
      return of();
    } else if (rangeSet.encloses(Range.<C>all())) {
      return all();
    }

    if (rangeSet instanceof ImmutableRangeSet) {
      ImmutableRangeSet<C> immutableRangeSet = (ImmutableRangeSet<C>) rangeSet;
      if (!immutableRangeSet.isPartialView()) {

    Range<Integer> rangeFour = Range.closedOpen(6, 7);

    ImmutableRangeSet.Builder<Integer> zis =
        ImmutableRangeSet.<Integer>builder().add(rangeOne).add(rangeTwo);
    ImmutableRangeSet.Builder<Integer> zat =
        ImmutableRangeSet.<Integer>builder().add(rangeThree).add(rangeFour);

    ImmutableRangeSet<Integer> rangeSet = zis.combine(zat).build();

    assertThat(rangeSet.asRanges())

  @GwtIncompatible
  private static final Collector<Range<Comparable<?>>, ?, ImmutableRangeSet<Comparable<?>>>
      TO_IMMUTABLE_RANGE_SET =
          Collector.of(
              ImmutableRangeSet::builder,
              ImmutableRangeSet.Builder::add,
              ImmutableRangeSet.Builder::combine,
              ImmutableRangeSet.Builder::build);

  // Lists

  @SuppressWarnings({"rawtypes", "unchecked"})

        return TreeRangeSet.create(contents);
      }
    },
    ImmutableRangeSetImpl {
      @Override
      <K extends Comparable<K>> RangeSet<K> create(RangeSet<K> contents) {
        return ImmutableRangeSet.copyOf(contents);
      }
    };

    abstract <K extends Comparable<K>> RangeSet<K> create(RangeSet<K> contents);
  }

  public enum SetMultimapImpl {
    HashMultimapImpl {
      @Override

        return TreeRangeSet.create(contents);
      }
    },
    ImmutableRangeSetImpl {
      @Override
      <K extends Comparable<K>> RangeSet<K> create(RangeSet<K> contents) {
        return ImmutableRangeSet.copyOf(contents);
      }
    };

    abstract <K extends Comparable<K>> RangeSet<K> create(RangeSet<K> contents);
  }

  public enum SetMultimapImpl {
    HashMultimapImpl {
      @Override