}
    ImmutableMap<V, K> backwardMap = builder.build();
    this.inverse = new RegularImmutableBiMap<V, K>(backwardMap, this);
  }

  RegularImmutableBiMap(ImmutableMap<K, V> delegate, ImmutableBiMap<V, K> inverse) {
    super(delegate);
    this.inverse = inverse;
  }

  @Override
  public ImmutableBiMap<V, K> inverse() {
    return inverse;
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testClearClearsInverse() {
    BiMap<V, K> inv = getMap().inverse();
    getMap().clear();
    assertTrue(getMap().isEmpty());
    assertTrue(inv.isEmpty());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testKeySetClearClearsInverse() {
    BiMap<V, K> inv = getMap().inverse();
    getMap().keySet().clear();
    assertTrue(getMap().isEmpty());
    assertTrue(inv.isEmpty());

  public abstract double transform(double x);

  /**
   * Returns the inverse linear transformation. The inverse of a horizontal transformation is a
   * vertical transformation, and vice versa. The inverse of the {@link #forNaN} transformation is
   * itself. In all other cases, the inverse is a transformation such that applying both the
   * original transformation and its inverse to a value gives you the original value give-or-take

    }
  }

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

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

  private final class Inverse extends IteratorBasedAbstractMap<V, K>
      implements BiMap<V, K>, Serializable {
    BiMap<K, V> forward() {

        .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);
  }

  /**

    assertEquals("one", copy.inverse().get(1));
    assertSame(copy, copy.inverse().inverse());
  }

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

  }

  public void testInverse() {
    BiMap<String, Integer> bimap = create();
    BiMap<Integer, String> inverse = bimap.inverse();
    assertSame(bimap, inverse.inverse());
    assertTrue(inverse instanceof SynchronizedBiMap);
    assertSame(mutex, ((SynchronizedBiMap<?, ?>) inverse).mutex);
  }

  @Override
  public void testValues() {
    BiMap<String, Integer> map = create();

      return oldValue;
    }
  }

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

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

  static class Inverse<K extends @Nullable Object, V extends @Nullable Object>
      extends AbstractMap<V, K> implements BiMap<V, K>, Serializable {

        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(),

  }

  public void testInverseMinimizesWork() {
    ImmutableSetMultimap<String, Character> multimap =
        ImmutableSetMultimap.of("of", 'o', "of", 'f', "to", 't', "to", 'o');
    assertSame(multimap.inverse(), multimap.inverse());
    assertSame(multimap, multimap.inverse().inverse());
  }

  private static <K, V> void assertMultimapEquals(