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;

                  @Override
                  Multimap<String, String> transform(Multimap<String, String> multimap) {
                    return Multimaps.transformEntries(multimap, ENTRY_TRANSFORMER);
                  }
                })
            .named("Multimaps.transformEntries[Multimap]")
            .withFeatures(
                CollectionSize.ANY,
                MapFeature.SUPPORTS_REMOVE,

                  @Override
                  Multimap<String, String> transform(Multimap<String, String> multimap) {
                    return Multimaps.transformEntries(multimap, ENTRY_TRANSFORMER);
                  }
                })
            .named("Multimaps.transformEntries[Multimap]")
            .withFeatures(
                CollectionSize.ANY,
                MapFeature.SUPPORTS_REMOVE,

import static com.google.common.collect.Multimaps.filterKeys;
import static com.google.common.collect.Multimaps.filterValues;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Predicate;
import java.util.Map.Entry;
import junit.framework.TestCase;

/**
 * Unit tests for {@link Multimaps} filtering methods.
 *
 * @author Jared Levy
 */

import static com.google.common.collect.Multimaps.filterKeys;
import static com.google.common.collect.Multimaps.filterValues;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Predicate;
import java.util.Map.Entry;
import junit.framework.TestCase;

/**
 * Unit tests for {@link Multimaps} filtering methods.
 *
 * @author Jared Levy
 */

   *
   * @throws NullPointerException if any key or value in {@code multimap} is null
   */
  public static <K, V> ImmutableSetMultimap<K, V> copyOf(
      Multimap<? extends K, ? extends V> multimap) {
    return copyOf(multimap, null);
  }

  private static <K, V> ImmutableSetMultimap<K, V> copyOf(
      Multimap<? extends K, ? extends V> multimap,
      @CheckForNull Comparator<? super V> valueComparator) {

   *
   * @throws NullPointerException if any key or value in {@code multimap} is null
   */
  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()) {

import com.google.common.collect.Iterators;
import com.google.common.collect.ListMultimap;
import com.google.common.collect.MapDifference;
import com.google.common.collect.Maps;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multimaps;
import com.google.common.collect.Multiset;
import com.google.common.collect.Ordering;
import com.google.common.collect.PeekingIterator;
import com.google.common.collect.Range;

   *
   * @throws NullPointerException if any key or value in {@code multimap} is null
   */
  public static <K, V> ImmutableListMultimap<K, V> copyOf(
      Multimap<? extends K, ? extends V> multimap) {
    if (multimap.isEmpty()) {
      return of();
    }

    // TODO(lowasser): copy ImmutableSetMultimap by using asList() on the sets
    if (multimap instanceof ImmutableListMultimap) {