return delegate.isEmpty();
  }

  @Override
  public final boolean containsKey(@Nullable Object key) {
    return Maps.safeContainsKey(delegate, key);
  }

  @Override
  public final boolean containsValue(@Nullable Object value) {
    return delegate.containsValue(value);
  }

  @Override
  public @Nullable V get(@Nullable Object key) {
    return (key == null) ? null : Maps.safeGet(delegate, key);
  }

   */
  public static <A extends @Nullable Object, B extends @Nullable Object, C extends @Nullable Object>
      Function<A, C> compose(Function<B, C> g, Function<A, ? extends B> f) {
    return new FunctionComposition<>(g, f);
  }

  private static final class FunctionComposition<
          A extends @Nullable Object, B extends @Nullable Object, C extends @Nullable Object>
      implements Function<A, C>, Serializable {

    }

    @Override
    @Nullable C correctedDoForward(@Nullable A a) {
      return second.correctedDoForward(first.correctedDoForward(a));
    }

    @Override
    @Nullable A correctedDoBackward(@Nullable C c) {
      return first.correctedDoBackward(second.correctedDoBackward(c));
    }

    @Override
    public boolean equals(@Nullable Object object) {

  }

  @Override
  public @Nullable V edgeValueOrDefault(N nodeU, N nodeV, @Nullable V defaultValue) {
    return edgeValueOrDefaultInternal(checkNotNull(nodeU), checkNotNull(nodeV), defaultValue);
  }

  @Override
  public @Nullable V edgeValueOrDefault(EndpointPair<N> endpoints, @Nullable V defaultValue) {
    validateEndpoints(endpoints);

  public E last() {
    return delegate.last();
  }

  @Override
  public @Nullable E lower(E e) {
    return delegate.lower(checkValid(e));
  }

  @Override
  public @Nullable E pollFirst() {
    return delegate.pollFirst();
  }

  @Override
  public @Nullable E pollLast() {
    return delegate.pollLast();
  }

  @Override
  public boolean remove(Object object) {

    }

    @Override
    public @Nullable T lower(T e) {
      return standardLower(e);
    }

    @Override
    public @Nullable T floor(T e) {
      return standardFloor(e);
    }

    @Override
    public @Nullable T ceiling(T e) {
      return standardCeiling(e);
    }

    @Override
    public @Nullable T higher(T e) {
      return standardHigher(e);
    }

import java.util.logging.Level;
import org.jspecify.annotations.Nullable;

/** Implementation of {@link Futures#immediateFuture}. */
@GwtCompatible
// TODO(cpovirk): Make this final (but that may break Mockito spy calls).
class ImmediateFuture<V extends @Nullable Object> implements ListenableFuture<V> {
  static final ListenableFuture<?> NULL = new ImmediateFuture<@Nullable Object>(null);

  }

  /**
   * Class for testing all permutations of nullable/non-nullable two-argument methods using
   * testMethod().
   *
   * <ul>
   *   <li>normalNormal: two params, neither is Nullable
   *   <li>nullableNormal: only first param is Nullable
   *   <li>normalNullable: only second param is Nullable
   *   <li>nullableNullable: both params are Nullable
   * </ul>
   */
  public static class TwoArg {

    public @Nullable E higher(@ParametricNullness E e) {
      return delegate.higher(e);
    }

    @Override
    public @Nullable E pollFirst() {
      throw new UnsupportedOperationException();
    }

    @Override
    public @Nullable E pollLast() {
      throw new UnsupportedOperationException();
    }

    @LazyInit private transient @Nullable UnmodifiableNavigableSet<E> descendingSet;

import org.jspecify.annotations.Nullable;

/**
 * Derived suite generators, split out of the suite builders so that they are available to GWT.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public final class DerivedCollectionGenerators {
  public static class MapEntrySetGenerator<K extends @Nullable Object, V extends @Nullable Object>