return of(Ordering.natural(), k1, v1);
  }

  /** Returns an immutable map containing a single entry. */
  private static <K, V> ImmutableSortedMap<K, V> of(Comparator<? super K> comparator, K k1, V v1) {
    return new ImmutableSortedMap<>(
        new RegularImmutableSortedSet<K>(ImmutableList.of(k1), checkNotNull(comparator)),
        ImmutableList.of(v1));

  public static <K, V> ImmutableListMultimap<K, V> of(K k1, V v1) {
    ImmutableListMultimap.Builder<K, V> builder = ImmutableListMultimap.builder();
    builder.put(k1, v1);
    return builder.build();
  }

  /** Returns an immutable multimap containing the given entries, in order. */
  public static <K, V> ImmutableListMultimap<K, V> of(K k1, V v1, K k2, V v2) {

   */
  public <K1 extends K, V1 extends V> CacheBuilder<K1, V1> removalListener(
      RemovalListener<? super K1, ? super V1> listener) {
    checkState(this.removalListener == null);

    // safely limiting the kinds of caches this can produce
    @SuppressWarnings("unchecked")
    CacheBuilder<K1, V1> me = (CacheBuilder<K1, V1>) this;
    me.removalListener = checkNotNull(listener);

    Entry<K, Collection<V>> asMapEntry0 = getOnlyElement(asMapEntrySet);
    assertTrue(multimap().put(k1(), v4()));
    assertTrue(asMapEntrySet.remove(asMapEntry0));
    assertEquals(1, multimap().size());
    assertContentsInOrder(multimap().keySet(), k1());
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)

  }

  /** Returns an immutable multimap containing a single entry. */
  public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1) {
    ImmutableSetMultimap.Builder<K, V> builder = ImmutableSetMultimap.builder();
    builder.put(k1, v1);
    return builder.build();
  }

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

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

  /**
   * Returns an immutable map containing the given entries, in order.
   *
   * @throws IllegalArgumentException if duplicate keys are provided
   */
  public static <K, V> ImmutableMap<K, V> of(K k1, V v1, K k2, V v2) {
    return RegularImmutableMap.fromEntries(entryOf(k1, v1), entryOf(k2, v2));
  }

  /**

  public static <K, V> ImmutableMultimap<K, V> of(K k1, V v1) {
    return ImmutableListMultimap.of(k1, v1);
  }

  /** Returns an immutable multimap containing the given entries, in order. */
  public static <K, V> ImmutableMultimap<K, V> of(K k1, V v1, K k2, V v2) {
    return ImmutableListMultimap.of(k1, v1, k2, v2);
  }

  /**

        assertNotSame(rr1, rr2);

        DefaultMavenMetadataCache.CacheKey k1 =
                new DefaultMavenMetadataCache.CacheKey(a1, false, lr1, Collections.singletonList(rr1));
        DefaultMavenMetadataCache.CacheKey k2 =
                new DefaultMavenMetadataCache.CacheKey(a2, false, lr2, Collections.singletonList(rr2));

        assertEquals(k1.hashCode(), k2.hashCode());
    }

    Entry<K, Collection<V>> asMapEntry0 = getOnlyElement(asMapEntrySet);
    assertTrue(multimap().put(k1(), v4()));
    assertTrue(asMapEntrySet.remove(asMapEntry0));
    assertEquals(1, multimap().size());
    assertContentsInOrder(multimap().keySet(), k1());
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)

            Collections.sort(list, (o1, o2) -> {
                final String k1 = o1.getKey();
                if (LANG_KEY.equals(k1)) {
                    return -1;
                }
                final String k2 = o2.getKey();
                if (LANG_KEY.equals(k2)) {
                    return -1;
                }
                return k1.compareTo(k2);
            });
            return new LinkedHashSet<>(list);