}
  }

  public void testAsMapGetImplementsSet() {
    for (K key : multimap().keySet()) {
      assertTrue(multimap().asMap().get(key) instanceof Set);
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testAsMapRemoveImplementsSet() {
    List<K> keys = new ArrayList<>(multimap().keySet());
    for (K key : keys) {
      resetCollection();

    assertMultimapRemainsUnmodified(multimap, originalEntries);

    // Test #keySet()
    assertSetIsUnmodifiable(multimap.keySet(), sampleKey);
    assertMultimapRemainsUnmodified(multimap, originalEntries);

    // Test #get()
    if (!multimap.isEmpty()) {
      K key = multimap.keySet().iterator().next();
      assertCollectionIsUnmodifiable(multimap.get(key), sampleValue);

    KeySet(final Map<K, Collection<V>> subMap) {
      super(subMap);
    }

    @Override
    public Iterator<K> iterator() {
      final Iterator<Entry<K, Collection<V>>> entryIterator = map().entrySet().iterator();
      return new Iterator<K>() {
        @CheckForNull Entry<K, Collection<V>> entry;

        @Override
        public boolean hasNext() {

  private final transient RegularImmutableSortedSet<K> keySet;
  private final transient ImmutableList<V> valueList;
  @CheckForNull private transient ImmutableSortedMap<K, V> descendingMap;

  ImmutableSortedMap(RegularImmutableSortedSet<K> keySet, ImmutableList<V> valueList) {
    this(keySet, valueList, null);
  }

  ImmutableSortedMap(
      RegularImmutableSortedSet<K> keySet,
      ImmutableList<V> valueList,

    return delegate().put(key, value);
  }

  @Override
  public void putAll(Map<? extends K, ? extends V> map) {
    delegate().putAll(map);
  }

  @Override
  public Set<K> keySet() {
    return delegate().keySet();
  }

  @Override
  public Collection<V> values() {
    return delegate().values();
  }

  @Override
  public Set<Entry<K, V>> entrySet() {
    return delegate().entrySet();

import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.Spliterator;
import java.util.function.Consumer;
import javax.annotation.CheckForNull;

/**
 * {@code keySet()} implementation for {@link ImmutableMap}.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault

    assertTrue(multimap().containsKey(k0()));
  }

  public void testContainsKeyNo() {
    assertFalse(multimap().containsKey(k3()));
  }

  public void testContainsKeysFromKeySet() {
    for (K k : multimap().keySet()) {
      assertTrue(multimap().containsKey(k));
    }
  }

  public void testContainsKeyAgreesWithGet() {
    for (K k : sampleKeys()) {
      assertEquals(!multimap().get(k).isEmpty(), multimap().containsKey(k));

    assertTrue(multimap().containsKey(k0()));
  }

  public void testContainsKeyNo() {
    assertFalse(multimap().containsKey(k3()));
  }

  public void testContainsKeysFromKeySet() {
    for (K k : multimap().keySet()) {
      assertTrue(multimap().containsKey(k));
    }
  }

  public void testContainsKeyAgreesWithGet() {
    for (K k : sampleKeys()) {
      assertEquals(!multimap().get(k).isEmpty(), multimap().containsKey(k));

  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testPutPresentKeyPropagatesToGet() {
    List<K> keys = Helpers.copyToList(multimap().keySet());
    for (K key : keys) {
      resetContainer();

      int size = getNumElements();

      Collection<V> collection = multimap().get(key);

    KeySet(final Map<K, Collection<V>> subMap) {
      super(subMap);
    }

    @Override
    public Iterator<K> iterator() {
      final Iterator<Entry<K, Collection<V>>> entryIterator = map().entrySet().iterator();
      return new Iterator<K>() {
        @CheckForNull Entry<K, Collection<V>> entry;

        @Override
        public boolean hasNext() {