*       Objects.equal}{@code (a, b)} implies that {@code predicate.apply(a) ==
   *       predicate.apply(b))}.
   * </ul>
   *
   * @throws NullPointerException if {@code input} is null and this predicate does not accept null
   *     arguments
   */
  boolean apply(@ParametricNullness T input);

  /**
   * Indicates whether another object is equal to this predicate.
   *

        String name, BiConsumer<T, Object> queryLambda, IntToDoubleFunction asymptotic) {
      return new QueryOp<T>() {
        @Override
        void apply(T collection, Object query) {
          queryLambda.accept(collection, query);
        }

        @Override
        double expectedAsymptotic(int n) {
          return asymptotic.applyAsDouble(n);
        }

        @Override

  /**
   * Compares two comparable objects as specified by {@link Comparable#compareTo}, <i>if</i> the
   * result of this comparison chain has not already been determined.
   *
   * <p>This method is declared to accept any 2 {@code Comparable} objects, even if they are not <a
   * href="https://docs.oracle.com/javase/tutorial/collections/interfaces/order.html">mutually

@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Predicates {
  private Predicates() {}

  // TODO(kevinb): considering having these implement a VisitablePredicate
  // interface which specifies an accept(PredicateVisitor) method.

  /** Returns a predicate that always evaluates to {@code true}. */
  @GwtCompatible(serializable = true)
  public static <T extends @Nullable Object> Predicate<T> alwaysTrue() {

    } else {
      return unsafeDoBackward(b);
    }
  }

  /*
   * LegacyConverter violates the contract of Converter by allowing its doForward and doBackward
   * methods to accept null. We could avoid having unchecked casts in Converter.java itself if we
   * could perform a cast to LegacyConverter, but we can't because it's an internal-only class.
   *

 * convenient shortcut methods defined directly on {@link HashFunction} to make this easier.
 *
 * <p>Hasher accepts primitive data types, but can also accept any Object of type {@code T} provided
 * that you implement a {@link Funnel}{@code <T>} to specify how to "feed" data from that object
 * into the function. (See {@linkplain Hasher#putObject an example} of this.)
 *

   * Number value = first.or(0.5); // fine
   * }</pre>
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this method is similar to Java 8's {@code
   * Optional.orElse}, but will not accept {@code null} as a {@code defaultValue} ({@link #orNull}
   * must be used instead). As a result, the value returned by this method is guaranteed non-null,
   * which is not the case for the {@code java.util} equivalent.
   */

   * Preconditions.checkNotNull.
   *
   * (verifyNotNull has many fewer "problem" callers, so we could try to be stricter. On the other
   * hand, verifyNotNull arguably has more reason to accept nullable arguments in the first
   * place....)
   */

  /**
   * Ensures that {@code reference} is non-null, throwing a {@code VerifyException} with a default
   * message otherwise.
   *

   * @return the count of the element before the operation; possibly zero
   * @throws IllegalArgumentException if {@code occurrences} is negative
   */
  /*
   * TODO(cpovirk): remove and removeExactly currently accept null inputs only
   * if occurrences == 0. This satisfies both NullPointerTester and
   * CollectionRemoveTester.testRemove_nullAllowed, but it's not clear that it's

  }

  @Override
  public void forEach(BiConsumer<? super K, ? super V> action) {
    checkNotNull(action);
    ImmutableList<K> keyList = keySet.asList();
    for (int i = 0; i < size(); i++) {
      action.accept(keyList.get(i), valueList.get(i));
    }
  }

  @Override
  @CheckForNull
  public V get(@CheckForNull Object key) {
    int index = keySet.indexOf(key);