* keys and values are the result of applying the provided mapping functions to the input
   * elements. The generated map is sorted by the specified comparator.
   *
   * <p>If the mapped keys contain duplicates (according to the specified comparator), an {@code
   * IllegalArgumentException} is thrown when the collection operation is performed. (This differs

   * keys and values are the result of applying the provided mapping functions to the input
   * elements. The generated map is sorted by the specified comparator.
   *
   * <p>If the mapped keys contain duplicates (according to the specified comparator), an {@code
   * IllegalArgumentException} is thrown when the collection operation is performed. (This differs

      }

      @Override
      public boolean contains(@CheckForNull Object element) {
        return set1.contains(element) && !set2.contains(element);
      }
    };
  }

  /**
   * Returns an unmodifiable <b>view</b> of the symmetric difference of two sets. The returned set
   * contains all elements that are contained in either {@code set1} or {@code set2} but not in

   * supports removal operations, and these are reflected in the underlying multimap.
   *
   * <p>It's acceptable for the underlying multimap to contain null keys, and even null values
   * provided that the function is capable of accepting null input. The transformed multimap might
   * contain null values, if the function sometimes gives a null result.
   *

      synchronized (mutex) {
        /*
         * toArrayImpl returns `@Nullable Object[]` rather than `Object[]` but only because it can
         * be used with collections that may contain null. This collection never contains nulls, so
         * we could return `Object[]`. But this class is private and J2KT cannot change return types
         * in overrides, so we declare `@Nullable Object[]` as the return type.
         */

  }

  int getConcurrencyLevel() {
    return (concurrencyLevel == UNSET_INT) ? DEFAULT_CONCURRENCY_LEVEL : concurrencyLevel;
  }

  /**
   * Specifies the maximum number of entries the cache may contain.
   *
   * <p>Note that the cache <b>may evict an entry before this limit is exceeded</b>. For example, in
   * the current implementation, when {@code concurrencyLevel} is greater than {@code 1}, each

        .inOrder();
  }

  public void testCartesianProduct_contains() {
    Set<List<Integer>> actual = Sets.cartesianProduct(set(1, 2), set(3, 4));
    assertTrue(actual.contains(list(1, 3)));
    assertTrue(actual.contains(list(1, 4)));
    assertTrue(actual.contains(list(2, 3)));
    assertTrue(actual.contains(list(2, 4)));
    assertFalse(actual.contains(list(3, 1)));
  }

  public void testCartesianProduct_equals() {

  }

  public void test_contains_nonnull_yes() {
    Iterator<@Nullable String> set = Arrays.<@Nullable String>asList("a", null, "b").iterator();
    assertTrue(Iterators.contains(set, "b"));
  }

  public void test_contains_nonnull_no() {
    Iterator<String> set = asList("a", "b").iterator();
    assertFalse(Iterators.contains(set, "c"));
  }

  public void test_contains_null_yes() {

    while (removeFrom.hasNext()) {
      if (!elementsToRetain.contains(removeFrom.next())) {
        removeFrom.remove();
        result = true;
      }
    }
    return result;
  }

  /**
   * Determines whether two iterators contain equal elements in the same order. More specifically,
   * this method returns {@code true} if {@code iterator1} and {@code iterator2} contain the same

   * successful input futures. The list of results is in the same order as the input list, and if
   * any of the provided futures fails or is canceled, its corresponding position will contain
   * {@code null} (which is indistinguishable from the future having a successful value of {@code
   * null}).
   *
   * <p>The list of results is in the same order as the input list.
   *