try {
      Stream.of(immutableCell("one", "uno", 1)).collect(collector);
      fail("Expected NullPointerException");
    } catch (NullPointerException expected) {
    }
    collector =
        TableCollectors.toImmutableTable(Cell::getRowKey, Cell::getColumnKey, Cell::getValue);
    try {
      Stream.of(immutableCell("one", "uno", 1), immutableCell("one", "uno", (Integer) null))
          .collect(collector);

  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.
   * When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
   * one specified is included.
   *
   * @throws NullPointerException if any element is null
   */
  public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1, E e2) {

    assertMapEquals(ImmutableSortedMap.of("one", 1), "one", 1);
    assertMapEquals(ImmutableSortedMap.of("one", 1, "two", 2), "one", 1, "two", 2);
    assertMapEquals(
        ImmutableSortedMap.of("one", 1, "two", 2, "three", 3), "one", 1, "three", 3, "two", 2);
    assertMapEquals(
        ImmutableSortedMap.of("one", 1, "two", 2, "three", 3, "four", 4),
        "four",
        4,
        "one",
        1,
        "three",

   *
   * <p>Duplicate elements are considered equal. For example, the list [1, 1] will have only one
   * permutation, instead of two. This is why the elements have to implement {@link Comparable}.
   *
   * <p>An empty iterable has only one permutation, which is an empty list.
   *
   * <p>This method is equivalent to {@code Collections2.orderedPermutations(list,
   * Ordering.natural())}.

    assertMultimapEquals(ImmutableListMultimap.of("one", 1), "one", 1);
    assertMultimapEquals(ImmutableListMultimap.of("one", 1, "two", 2), "one", 1, "two", 2);
    assertMultimapEquals(
        ImmutableListMultimap.of("one", 1, "two", 2, "three", 3), "one", 1, "two", 2, "three", 3);
    assertMultimapEquals(
        ImmutableListMultimap.of("one", 1, "two", 2, "three", 3, "four", 4),
        "one",
        1,
        "two",
        2,

    assertMultimapEquals(ImmutableSetMultimap.of("one", 1), "one", 1);
    assertMultimapEquals(ImmutableSetMultimap.of("one", 1, "two", 2), "one", 1, "two", 2);
    assertMultimapEquals(
        ImmutableSetMultimap.of("one", 1, "two", 2, "three", 3), "one", 1, "two", 2, "three", 3);
    assertMultimapEquals(
        ImmutableSetMultimap.of("one", 1, "two", 2, "three", 3, "four", 4),
        "one",
        1,
        "two",
        2,

            .withFeatures(
                CollectionFeature.ALLOWS_NULL_VALUES,
                CollectionFeature.GENERAL_PURPOSE,
                CollectionFeature.KNOWN_ORDER,
                CollectionSize.ONE,
                CollectionSize.SEVERAL)
            .createTestSuite());
    suite.addTestSuite(TreeMultimapNaturalTest.class);
    return suite;
  }

  protected SetMultimap<String, Integer> create() {

  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.
   * When multiple elements are equivalent according to {@link Comparable#compareTo}, only the first
   * one specified is included.
   *
   * @throws NullPointerException if any element is null
   */
  public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1, E e2) {

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

    try {
      Ordering.explicit(1, 2, 3, 4, 2);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  // A more limited test than the one that follows, but this one uses the
  // actual public API.
  @J2ktIncompatible // Ordering.arbitrary
  public void testArbitrary_withoutCollisions() {
    List<Object> list = Lists.newArrayList();
    for (int i = 0; i < 50; i++) {