import com.google.common.collect.ImmutableSetMultimap;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.MultimapBuilder;
import com.google.common.collect.Multimaps;
import com.google.common.collect.Multiset;
import com.google.common.collect.Ordering;
import com.google.common.collect.SetMultimap;
import com.google.common.util.concurrent.Service.State;

    multimap.put("foo", -1);
    multimap.put(null, null);
    multimap.put("bar", 1);
    multimap.put("foo", 2);
    multimap.put(null, 0);
    multimap.put("bar", 2);
    multimap.put("bar", null);
    multimap.put("foo", null);
    multimap.put("foo", 4);
    multimap.put(null, -1);
    multimap.put("bar", 3);
    multimap.put("bar", 1);
    multimap.put("foo", 1);

    assertEquals(

   */
  static <K extends @Nullable Object, V extends @Nullable Object> void writeMultimap(
      Multimap<K, V> multimap, ObjectOutputStream stream) throws IOException {
    stream.writeInt(multimap.asMap().size());
    for (Map.Entry<K, Collection<V>> entry : multimap.asMap().entrySet()) {
      stream.writeObject(entry.getKey());
      stream.writeInt(entry.getValue().size());

    checkNotNull(multimapSupplier);
    return Collector.of(
        multimapSupplier,
        (multimap, input) -> multimap.put(keyFunction.apply(input), valueFunction.apply(input)),
        (multimap1, multimap2) -> {
          multimap1.putAll(multimap2);
          return multimap1;
        });
  }

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

   */
  static <K extends @Nullable Object, V extends @Nullable Object> void writeMultimap(
      Multimap<K, V> multimap, ObjectOutputStream stream) throws IOException {
    stream.writeInt(multimap.asMap().size());
    for (Map.Entry<K, Collection<V>> entry : multimap.asMap().entrySet()) {
      stream.writeObject(entry.getKey());
      stream.writeInt(entry.getValue().size());

   * the same mappings as the specified multimap.
   *
   * @param multimap the multimap whose contents are copied to this multimap
   */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create(
      Multimap<? extends K, ? extends V> multimap) {

    TreeMultimap<String, Integer> multimap = TreeMultimap.create();
    multimap.put("google", 2);
    multimap.put("google", 6);
    multimap.put("foo", 3);
    multimap.put("foo", 1);
    multimap.put("foo", 7);
    multimap.put("tree", 4);
    multimap.put("tree", 0);
    return multimap;
  }

  public void testToString() {
    SetMultimap<String, Integer> multimap = create();

import com.google.common.collect.ImmutableMultiset;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multimaps;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.Immutable;
import com.google.errorprone.annotations.concurrent.LazyInit;

   * key-value mapping appears multiple times in the input multimap, it only appears once in the
   * constructed multimap. The new multimap has the same {@link Multimap#entries()} iteration order
   * as the input multimap, except for excluding duplicate mappings.
   *
   * @param multimap the multimap whose contents are copied to this multimap
   */

   * assertThat(colorForName).containsEntry("red", red);
   * }</pre>
   *
   * <p>If your index may associate multiple values with each key, use {@link
   * Multimaps#index(Iterable, Function) Multimaps.index}.
   *
   * <p><b>Note:</b> on Java 8+, it is usually better to use streams. For example:
   *
   * <pre>{@code
   * import static com.google.common.collect.ImmutableMap.toImmutableMap;