Multimap<K, V> synchronizedMultimap(Multimap<K, V> multimap) {
    return Synchronized.multimap(multimap, null);
  }

  /**
   * Returns an unmodifiable view of the specified multimap. Query operations on the returned
   * multimap "read through" to the specified multimap, and attempts to modify the returned
   * multimap, either directly or through the multimap's views, result in an {@code

      Multimap<K, V> synchronizedMultimap(Multimap<K, V> multimap) {
    return Synchronized.multimap(multimap, null);
  }

  /**
   * Returns an unmodifiable view of the specified multimap. Query operations on the returned
   * multimap "read through" to the specified multimap, and attempts to modify the returned
   * multimap, either directly or through the multimap's views, result in an {@code

    multimap.put("bar", 5);
    multimap.put("bar", -1);
    multimap.put(nullKey, nullValue);
    multimap.put("foo", nullValue);
    multimap.put(nullKey, 5);
    multimap.put("foo", 2);

    if (permitsDuplicates) {
      assertEquals(9, multimap.size());
    } else {
      assertEquals(8, multimap.size());
    }

    Multimap<@Nullable String, @Nullable Integer> unmodifiable;

     * present?
     */

    if (multimap.isEmpty()) {
      return of();
    }

    if (multimap instanceof ImmutableSetMultimap) {
      @SuppressWarnings("unchecked") // safe since multimap is not writable
      ImmutableSetMultimap<K, V> kvMultimap = (ImmutableSetMultimap<K, V>) multimap;
      if (!kvMultimap.isPartialView()) {
        return kvMultimap;
      }
    }

   */
  public static <K, V> ImmutableMultimap<K, V> copyOf(Multimap<? extends K, ? extends V> multimap) {
    if (multimap instanceof ImmutableMultimap) {
      @SuppressWarnings("unchecked") // safe since multimap is not writable
      ImmutableMultimap<K, V> kvMultimap = (ImmutableMultimap<K, V>) multimap;
      if (!kvMultimap.isPartialView()) {
        return kvMultimap;

    Multimap<String, Integer> multimap = createMultimap();
    return multimap.asMap();
  }

  @Override
  protected Map<String, Collection<Integer>> makePopulatedMap() {
    Multimap<String, Integer> multimap = createMultimap();
    populate(multimap);
    return multimap.asMap();
  }

    TreeMultimap<@Nullable String, @Nullable Integer> multimap =
        TreeMultimap.create(StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
    multimap.put("google", 2);
    multimap.put("google", 6);
    multimap.put(null, 3);
    multimap.put(null, 1);
    multimap.put(null, 7);
    multimap.put("tree", 0);
    multimap.put("tree", null);
    return multimap;
  }

     * present?
     */

    if (multimap.isEmpty()) {
      return of();
    }

    if (multimap instanceof ImmutableSetMultimap) {
      @SuppressWarnings("unchecked") // safe since multimap is not writable
      ImmutableSetMultimap<K, V> kvMultimap = (ImmutableSetMultimap<K, V>) multimap;
      if (!kvMultimap.isPartialView()) {
        return kvMultimap;
      }
    }

  }

  public void testMultimapReads() {
    Multimap<String, Integer> multimap = createMultimap();
    assertTrue(multimap.containsKey("foo"));
    assertFalse(multimap.containsKey("cat"));
    assertTrue(multimap.containsValue(1));
    assertFalse(multimap.containsValue(5));
    assertTrue(multimap.containsEntry("foo", 1));
    assertFalse(multimap.containsEntry("cat", 1));

    assertTrue(multimap.containsEntry("foo", 1));
    assertFalse(multimap.containsEntry("cat", 1));
    assertFalse(multimap.containsEntry("foo", 5));
    assertFalse(multimap.entries().isEmpty());
    assertEquals(3, multimap.size());
    assertFalse(multimap.isEmpty());
    assertThat(multimap.toString()).isEqualTo("{foo=[1, 3], bar=[2]}");
  }

  public void testMultimapWrites() {