public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2) {
    return new RegularImmutableBiMap<K, V>(ImmutableMap.of(k1, v1, k2, v2));
  }

  public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3) {
    return new RegularImmutableBiMap<K, V>(ImmutableMap.of(k1, v1, k2, v2, k3, v3));
  }

  public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {

    return new RegularImmutableMap<K, V>(entryOf(k1, v1), entryOf(k2, v2));
  }

  public static <K, V> ImmutableMap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3) {
    return new RegularImmutableMap<K, V>(entryOf(k1, v1), entryOf(k2, v2), entryOf(k3, v3));
  }

  public static <K, V> ImmutableMap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {

   */
  public static <K extends Comparable<? super K>, V> ImmutableSortedMap<K, V> of(
      K k1, V v1, K k2, V v2) {
    return fromEntries(entryOf(k1, v1), entryOf(k2, v2));
  }

  /**
   * Returns an immutable sorted map containing the given entries, sorted by the natural ordering of
   * their keys.
   *

   * an entry (according to {@link Object#equals}) after the first are ignored.
   */
  public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1, K k2, V v2) {
    ImmutableSetMultimap.Builder<K, V> builder = ImmutableSetMultimap.builder();
    builder.put(k1, v1);
    builder.put(k2, v2);
    return builder.build();
  }

  /**
   * Returns an immutable multimap containing the given entries, in order. Repeated occurrences of

    assertEmpty(result);

    assertTrue(result.add(v1()));
    assertTrue(result.add(v2()));

    assertContentsAnyOrder(result, v1(), v2());
    assertContentsAnyOrder(multimap().get(k0()), v1(), v2());
    assertTrue(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));
    assertTrue(multimap().containsEntry(k0(), v2()));
    assertEquals(oldSize + 1, multimap().size());
  }

   *
   * @throws IllegalArgumentException if duplicate keys or values are added
   */
  public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2) {
    checkEntryNotNull(k1, v1);
    checkEntryNotNull(k2, v2);
    return new RegularImmutableBiMap<K, V>(new Object[] {k1, v1, k2, v2}, 2);
  }

  /**
   * Returns an immutable map containing the given entries, in order.
   *

    <V1, V2, U> ClosingFunction2<V1, V2, U> waitFor(ClosingFunction2<V1, V2, U> closingFunction2) {
      return waitFor(closingFunction2, ClosingFunction2.class);
    }

    @SuppressWarnings("unchecked") // proxy for a generic class
    <V1, V2, U> AsyncClosingFunction2<V1, V2, U> waitFor(
        AsyncClosingFunction2<V1, V2, U> asyncClosingFunction2) {

    assertEmpty(result);

    assertTrue(result.add(v1()));
    assertTrue(result.add(v2()));

    assertContentsAnyOrder(result, v1(), v2());
    assertContentsAnyOrder(multimap().get(k0()), v1(), v2());
    assertTrue(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));
    assertTrue(multimap().containsEntry(k0(), v2()));
    assertEquals(oldSize + 1, multimap().size());
  }

   *
   * @throws IllegalArgumentException if duplicate keys are provided
   */
  public static <K, V> ImmutableMap<K, V> of(K k1, V v1, K k2, V v2) {
    checkEntryNotNull(k1, v1);
    checkEntryNotNull(k2, v2);
    return RegularImmutableMap.create(2, new Object[] {k1, v1, k2, v2});
  }

  /**
   * Returns an immutable map containing the given entries, in order.
   *

    return TableCollectors.<T, R, C, V, I>toTable(
        rowFunction,
        columnFunction,
        valueFunction,
        (v1, v2) -> {
          throw new IllegalStateException("Conflicting values " + v1 + " and " + v2);
        },
        tableSupplier);
  }

  static <
          T extends @Nullable Object,
          R extends @Nullable Object,