}

  AbstractBiMap<V, K> makeInverse(Map<V, K> backward) {
    return new Inverse<>(backward, this);
  }

  void setInverse(AbstractBiMap<V, K> inverse) {
    this.inverse = inverse;
  }

  // Query Operations (optimizations)

  @Override
  public boolean containsValue(@Nullable Object value) {
    return inverse.containsKey(value);
  }

  // Modification Operations

  }

  AbstractBiMap<V, K> makeInverse(Map<V, K> backward) {
    return new Inverse<>(backward, this);
  }

  void setInverse(AbstractBiMap<V, K> inverse) {
    this.inverse = inverse;
  }

  // Query Operations (optimizations)

  @Override
  public boolean containsValue(@Nullable Object value) {
    return inverse.containsKey(value);
  }

  // Modification Operations

    assertThat(copy.inverse().get(1)).isEqualTo("one");
    assertThat(copy.inverse().inverse()).isSameInstanceAs(copy);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testInverseSerialization() {
    ImmutableBiMap<String, Integer> bimap =
        ImmutableBiMap.copyOf(ImmutableMap.of(1, "one", 2, "two")).inverse();

    final HashBiMap<K, V> obverse;

    Inverse(HashBiMap<K, V> obverse) {
      this.obverse = obverse;
    }

    @Override
    public int size() {
      return obverse.size;
    }

    @Override
    public void clear() {
      obverse.clear();
    }

    @Override
    public boolean containsKey(@Nullable Object key) {
      Object obverseValue = key;

  @LazyInit @RetainedWith private transient @Nullable ImmutableBiMap<V, K> inverse;

  @Override
  public ImmutableBiMap<V, K> inverse() {
    if (isEmpty()) {
      return ImmutableBiMap.of();
    }
    ImmutableBiMap<V, K> result = inverse;
    return (result == null) ? inverse = new Inverse() : result;
  }

  private final class Inverse extends ImmutableBiMap<V, K> {

    @Override
    public int size() {

        .inOrder();
    // backward map ordered by country
    assertThat(bimap.inverse().keySet())
        .containsExactly(Country.CANADA, Country.CHILE, Country.SWITZERLAND)
        .inOrder();
    // backward map ordered by country (even for currency values)
    assertThat(bimap.inverse().values())
        .containsExactly(Currency.DOLLAR, Currency.PESO, Currency.FRANC)
        .inOrder();
  }

        ImmutableListMultimap.<String, Integer>of().inverse());
    assertEquals(ImmutableListMultimap.of(1, "one"), ImmutableListMultimap.of("one", 1).inverse());
    assertEquals(
        ImmutableListMultimap.of(1, "one", 2, "two"),
        ImmutableListMultimap.of("one", 1, "two", 2).inverse());
    assertEquals(
        ImmutableListMultimap.of("of", 'o', "of", 'f', "to", 't', "to", 'o').inverse(),

      return oldValue;
    }
  }

  @LazyInit @RetainedWith private transient @Nullable BiMap<V, K> inverse;

  @Override
  public BiMap<V, K> inverse() {
    BiMap<V, K> result = inverse;
    return (result == null) ? inverse = new Inverse<>(this) : result;
  }

  private static final class Inverse<K extends @Nullable Object, V extends @Nullable Object>

        .isWithin(ALLOWED_ERROR)
        .of(x1 + xDelta);
    assertThat(transformation.slope()).isWithin(ALLOWED_ERROR).of(yDelta / xDelta);
    assertThat(transformation.inverse().slope()).isWithin(ALLOWED_ERROR).of(xDelta / yDelta);
    assertThat(transformation.inverse()).isSameInstanceAs(transformation.inverse());
    assertThat(transformation.inverse().inverse()).isSameInstanceAs(transformation);
  }

  /**

        ImmutableListMultimap.<String, Integer>of().inverse());
    assertEquals(ImmutableListMultimap.of(1, "one"), ImmutableListMultimap.of("one", 1).inverse());
    assertEquals(
        ImmutableListMultimap.of(1, "one", 2, "two"),
        ImmutableListMultimap.of("one", 1, "two", 2).inverse());
    assertEquals(
        ImmutableListMultimap.of("of", 'o', "of", 'f', "to", 't', "to", 'o').inverse(),