this.function = checkNotNull(function);
    }

    /**
     * The default implementation inherited is based on iteration and removal of each element which
     * can be overkill. That's why we forward this call directly to the backing list.
     */
    @Override
    protected void removeRange(int fromIndex, int toIndex) {
      fromList.subList(fromIndex, toIndex).clear();
    }

    @Override

import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@link ImmutableSetMultimap}.
 *
 * @author Mike Ward
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class ImmutableSetMultimapTest extends TestCase {
  private static final class ImmutableSetMultimapGenerator extends TestStringSetMultimapGenerator {

  private final ImmutableSortedSet<E> forward;

  DescendingImmutableSortedSet(ImmutableSortedSet<E> forward) {
    super(Ordering.from(forward.comparator()).reverse());
    this.forward = forward;
  }

  @Override
  public boolean contains(@CheckForNull Object object) {
    return forward.contains(object);
  }

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

  @Override

 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingNavigableSet} forward <i>indiscriminately</i>
 * to the methods of the delegate. For example, overriding {@link #add} alone <i>will not</i> change
 * the behavior of {@link #addAll}, which can lead to unexpected behavior. In this case, you should

  /** Package-private constructor for creating a map-backed bimap. */
  AbstractBiMap(Map<K, V> forward, Map<V, K> backward) {
    setDelegates(forward, backward);
  }

  /** Private constructor for inverse bimap. */
  private AbstractBiMap(Map<K, V> backward, AbstractBiMap<V, K> forward) {
    delegate = backward;
    inverse = forward;
  }

  @Override
  protected Map<K, V> delegate() {
    return delegate;
  }

    BiMapPair<K, V> copy = SerializableTester.reserialize(pair);
    assertEquals(pair.forward, copy.forward);
    assertEquals(pair.backward, copy.backward);
    assertSame(copy.backward, copy.forward.inverse());
    assertSame(copy.forward, copy.backward.inverse());
  }

  private static class BiMapPair<K, V> implements Serializable {
    final BiMap<K, V> forward;
    final BiMap<V, K> backward;

    BiMapPair(BiMap<K, V> original) {

    BiMapPair<K, V> copy = SerializableTester.reserialize(pair);
    assertEquals(pair.forward, copy.forward);
    assertEquals(pair.backward, copy.backward);
    assertSame(copy.backward, copy.forward.inverse());
    assertSame(copy.forward, copy.backward.inverse());
  }

  private static class BiMapPair<K, V> implements Serializable {
    final BiMap<K, V> forward;
    final BiMap<V, K> backward;

    BiMapPair(BiMap<K, V> original) {

 * the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingSortedMultiset} forward
 * <b>indiscriminately</b> to the methods of the delegate. For example, overriding {@link
 * #add(Object, int)} alone <b>will not</b> change the behavior of {@link #add(Object)}, which can

 * <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingSortedSet} forward <i>indiscriminately</i> to
 * the methods of the delegate. For example, overriding {@link #add} alone <i>will not</i> change
 * the behavior of {@link #addAll}, which can lead to unexpected behavior. In this case, you should

            Currency.FRANC, Country.SWITZERLAND);
    EnumBiMap<Currency, Country> bimap = EnumBiMap.create(map);

    // forward map ordered by currency
    assertThat(bimap.keySet())
        .containsExactly(Currency.DOLLAR, Currency.FRANC, Currency.PESO)
        .inOrder();
    // forward map ordered by currency (even for country values)
    assertThat(bimap.values())