public ImmutableListMultimap<String, String> parameters() {
    return parameters;
  }

  private Map<String, ImmutableMultiset<String>> parametersAsMap() {
    return Maps.transformValues(parameters.asMap(), ImmutableMultiset::copyOf);
  }

  /**
   * Returns an optional charset for the value of the charset parameter if it is specified.
   *

      }
    },
    ImmutableMultisetImpl {
      @Override
      public <E extends Comparable<E>> Multiset<E> create(Collection<E> contents) {
        return ImmutableMultiset.copyOf(contents);
      }
    };
  }

  enum SortedMultisetImpl implements CollectionsImplEnum {
    TreeMultisetImpl {
      @Override

  public ImmutableListMultimap<String, String> parameters() {
    return parameters;
  }

  private Map<String, ImmutableMultiset<String>> parametersAsMap() {
    return Maps.transformValues(parameters.asMap(), ImmutableMultiset::copyOf);
  }

  /**
   * Returns an optional charset for the value of the charset parameter if it is specified.
   *

 *       ordering is otherwise specified (e.g. {@link ImmutableSortedSet#naturalOrder}). See the
 *       appropriate factory method for details. View collections such as {@link
 *       ImmutableMultiset#elementSet} iterate in the same order as the parent, except as noted.
 *   <li><b>Thread safety.</b> It is safe to access this collection concurrently from multiple
 *       threads.

 *       ordering is otherwise specified (e.g. {@link ImmutableSortedSet#naturalOrder}). See the
 *       appropriate factory method for details. View collections such as {@link
 *       ImmutableMultiset#elementSet} iterate in the same order as the parent, except as noted.
 *   <li><b>Thread safety.</b> It is safe to access this collection concurrently from multiple
 *       threads.

 * element (in a way that affects its {@link Object#equals} behavior) while it is contained in a
 * multiset. Undefined behavior and bugs will result.
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableMultiset}
 *   <li>{@link ImmutableSortedMultiset}
 *   <li>{@link HashMultiset}
 *   <li>{@link LinkedHashMultiset}
 *   <li>{@link TreeMultiset}
 *   <li>{@link EnumMultiset}
 *   <li>{@link ConcurrentHashMultiset}

 * element (in a way that affects its {@link Object#equals} behavior) while it is contained in a
 * multiset. Undefined behavior and bugs will result.
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableMultiset}
 *   <li>{@link ImmutableSortedMultiset}
 *   <li>{@link HashMultiset}
 *   <li>{@link LinkedHashMultiset}
 *   <li>{@link TreeMultiset}
 *   <li>{@link EnumMultiset}
 *   <li>{@link ConcurrentHashMultiset}

    assertSame(immutableList, Iterables.unmodifiableIterable((List<String>) immutableList));
  }

  public void testFrequency_multiset() {
    Multiset<String> multiset = ImmutableMultiset.of("a", "b", "a", "c", "b", "a");
    assertEquals(3, frequency(multiset, "a"));
    assertEquals(2, frequency(multiset, "b"));
    assertEquals(1, frequency(multiset, "c"));

    assertSame(immutableList, Iterables.unmodifiableIterable((List<String>) immutableList));
  }

  public void testFrequency_multiset() {
    Multiset<String> multiset = ImmutableMultiset.of("a", "b", "a", "c", "b", "a");
    assertEquals(3, frequency(multiset, "a"));
    assertEquals(2, frequency(multiset, "b"));
    assertEquals(1, frequency(multiset, "c"));