@ElementTypesAreNonnullByDefault
public class ImmutableRangeMap<K extends Comparable<?>, V> implements RangeMap<K, V>, Serializable {

  private static final ImmutableRangeMap<Comparable<?>, Object> EMPTY =
      new ImmutableRangeMap<>(ImmutableList.<Range<Comparable<?>>>of(), ImmutableList.of());

  /**
   * Returns a {@code Collector} that accumulates the input elements into a new {@code

      Collector<T, ?, ImmutableRangeMap<K, V>> toImmutableRangeMap(
          Function<? super T, Range<K>> keyFunction,
          Function<? super T, ? extends V> valueFunction) {
    checkNotNull(keyFunction);
    checkNotNull(valueFunction);
    return Collector.of(
        ImmutableRangeMap::<K, V>builder,

    assertEquals(rangeMap.asMapOfRanges(), copy.asMapOfRanges());
  }

  public void testCopyOfImmutableRangeMap() {
    ImmutableRangeMap<Integer, Integer> rangeMap =
        ImmutableRangeMap.<Integer, Integer>builder()
            .put(Range.open(3, 7), 1)
            .put(Range.closed(9, 10), 2)
            .put(Range.closed(12, 16), 3)
            .build();