// of the lists that needs to be serialized.
  private ImmutableBiMap<V, K> inverse;

  @SuppressWarnings("unchecked") // used only for the empty map, which works for any types
  RegularImmutableBiMap() {
    super(new RegularImmutableMap<K, V>(new HashMap<K, V>()));
    this.inverse = (ImmutableBiMap<V, K>) this;
  }

  RegularImmutableBiMap(ImmutableMap<K, V> delegate) {

import java.util.List;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.junit.Ignore;

/**
 * Tester to make sure the {@code iterator().remove()} implementation of {@code Multiset} works when
 * there are multiple occurrences of elements.
 *
 * @author Louis Wasserman
 */
@GwtCompatible(emulated = true)
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

    return contents.getEntry(index);
  }

  @GwtIncompatible
  private static class SerializedForm implements Serializable {
    final Object[] elements;
    final int[] counts;

    // "extends Object" works around https://github.com/typetools/checker-framework/issues/3013
    SerializedForm(Multiset<? extends Object> multiset) {
      int distinct = multiset.entrySet().size();
      elements = new Object[distinct];

      fail("setValue on unmodifiable Map.Entry succeeded");
    } catch (UnsupportedOperationException expected) {
    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *
   * <p>This test only works with iterators that iterate over a finite set.
   */
  public static void assertIteratorIsUnmodifiable(Iterator<?> iterator) {
    while (iterator.hasNext()) {
      iterator.next();
      try {
        iterator.remove();

    ImmutableTypeToInstanceMap<Iterable<?>[]> map =
        ImmutableTypeToInstanceMap.<Iterable<?>[]>builder().put(type, array).build();
    assertEquals(1, map.size());
    // Redundant cast works around a javac bug.
    assertThat((Iterable<?>[]) map.getInstance(type)).asList().containsExactly(array[0]);
  }

  public void testWildcardType() {

  }

  // TODO(cpovirk): instead of skipping, use a smaller number of steps
  @GwtIncompatible // works but takes 5 minutes to run
  public void testPeekingIteratorBehavesLikeIteratorOnThreeElementIterable() {
    actsLikeIteratorHelper(Lists.newArrayList("A", "B", "C"));
  }

  @GwtIncompatible // works but takes 5 minutes to run
  public void testPeekingIteratorAcceptsNullElements() {

    ImmutableTypeToInstanceMap<Iterable<?>[]> map =
        ImmutableTypeToInstanceMap.<Iterable<?>[]>builder().put(type, array).build();
    assertEquals(1, map.size());
    // Redundant cast works around a javac bug.
    assertThat((Iterable<?>[]) map.getInstance(type)).asList().containsExactly(array[0]);
  }

  public void testWildcardType() {

          public <T extends @Nullable Object> T[] toArray(T[] array) {
            T[] result = super.toArray(array);
            if (size() < result.length) {
              // It works around a GWT bug where elements after last is not
              // properly null'ed.
              @Nullable Object[] unsoundlyCovariantArray = result;
              unsoundlyCovariantArray[size()] = null;
            }

      fail("setValue on unmodifiable Map.Entry succeeded");
    } catch (UnsupportedOperationException expected) {
    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *
   * <p>This test only works with iterators that iterate over a finite set.
   */
  public static void assertIteratorIsUnmodifiable(Iterator<?> iterator) {
    while (iterator.hasNext()) {
      iterator.next();
      try {
        iterator.remove();

    return Collectors.collectingAndThen(
        Collectors.toMap(keyFunction, valueFunction, mergeFunction, LinkedHashMap::new),
        ImmutableMap::copyOf);
  }

  @SuppressWarnings("unchecked") // An empty map works for all types.
  public static <K, V> ImmutableMap<K, V> of() {
    return (ImmutableMap<K, V>) RegularImmutableMap.EMPTY;
  }

  public static <K, V> ImmutableMap<K, V> of(K k1, V v1) {