.put(ImmutableSortedSet.class, ImmutableSortedSet.of())
          .put(NavigableSet.class, Sets.unmodifiableNavigableSet(Sets.newTreeSet()))
          .put(Map.class, ImmutableMap.of())
          .put(ImmutableMap.class, ImmutableMap.of())
          .put(SortedMap.class, ImmutableSortedMap.of())
          .put(ImmutableSortedMap.class, ImmutableSortedMap.of())

    new EqualsTester()
        .addEqualityGroup(
            ImmutableMap.of(),
            ImmutableMap.builder().buildOrThrow(),
            ImmutableMap.ofEntries(),
            map())
        .addEqualityGroup(
            ImmutableMap.of(1, 1),
            ImmutableMap.builder().put(1, 1).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1)),
            map(1, 1))
        .addEqualityGroup(

    assertEquals(
        ImmutableMap.of(Range.closedOpen(5, 7), 1, Range.closed(9, 10), 2), sub.asMapOfRanges());
    sub.put(Range.closed(7, 9), 4);
    assertEquals(
        ImmutableMap.of(
            Range.closedOpen(5, 7), 1, Range.closed(7, 9), 4, Range.openClosed(9, 10), 2),
        sub.asMapOfRanges());
    assertEquals(
        ImmutableMap.of(
            Range.open(3, 7),
            1,

    assertEquals(ImmutableMap.of(1, 'a', 3, 'c'), row);
    assertEquals(ImmutableMap.of(3, 'c'), subRow);
    table.remove("foo", 3);
    assertEquals(ImmutableMap.of(1, 'a'), row);
    assertEquals(ImmutableMap.of(), subRow);
    table.remove("foo", 1);
    assertEquals(ImmutableMap.of(), row);
    assertEquals(ImmutableMap.of(), subRow);
    table.put("foo", 2, 'b');

    Map<String, String> map =
        transformValues(ImmutableMap.<String, Integer>of(), Functions.toStringFunction());
    assertMapsEqual(new HashMap<>(), map);
  }

  public void testTransformSingletonMapEquality() {
    Map<String, String> map =
        transformValues(ImmutableMap.of("a", 1), Functions.toStringFunction());
    Map<String, String> expected = ImmutableMap.of("a", "1");
    assertMapsEqual(expected, map);

    new EqualsTester()
        .addEqualityGroup(
            EnumBiMap.create(ImmutableMap.of(Currency.DOLLAR, Country.CANADA)),
            EnumBiMap.create(ImmutableMap.of(Currency.DOLLAR, Country.CANADA)))
        .addEqualityGroup(EnumBiMap.create(ImmutableMap.of(Currency.DOLLAR, Country.CHILE)))
        .addEqualityGroup(EnumBiMap.create(ImmutableMap.of(Currency.FRANC, Country.CANADA)))
        .testEquals();
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testForMapWithDefaultSerializable() {
    checkCanReserialize(Functions.forMap(ImmutableMap.of(1, 2), 3));
  }

  public void testForMapWithDefault_null() {
    ImmutableMap<String, Integer> map = ImmutableMap.of("One", 1);
    Function<String, @Nullable Integer> function = Functions.forMap(map, null);

    assertEquals((Integer) 1, function.apply("One"));

    Map<String, String> map =
        transformValues(ImmutableMap.<String, Integer>of(), Functions.toStringFunction());
    assertMapsEqual(new HashMap<>(), map);
  }

  public void testTransformSingletonMapEquality() {
    Map<String, String> map =
        transformValues(ImmutableMap.of("a", 1), Functions.toStringFunction());
    Map<String, String> expected = ImmutableMap.of("a", "1");
    assertMapsEqual(expected, map);

  }

  @Override
  public ImmutableSet<R> rowKeySet() {
    return rowMap().keySet();
  }

  /**
   * {@inheritDoc}
   *
   * <p>The value {@code Map<C, V>} instances in the returned map are {@link ImmutableMap} instances
   * as well.
   */
  @Override
  public abstract ImmutableMap<R, Map<C, V>> rowMap();

  @Override

        ImmutableMap.Builder::combine,
        ImmutableMap.Builder::buildOrThrow);
  }

  static <T extends @Nullable Object, K, V> Collector<T, ?, ImmutableMap<K, V>> toImmutableMap(
      Function<? super T, ? extends K> keyFunction,
      Function<? super T, ? extends V> valueFunction,
      BinaryOperator<V> mergeFunction) {
    checkNotNull(keyFunction);
    checkNotNull(valueFunction);
    checkNotNull(mergeFunction);