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

 *
 * <p>As with {@code Map}, the behavior of a {@code Multimap} is not specified if key objects
 * already present in the multimap change in a manner that affects {@code equals} comparisons. Use
 * caution if mutable objects are used as keys in a {@code Multimap}.
 *
 * <p>All methods that modify the multimap are optional. The view collections returned by the

 *
 * <p>As with {@code Map}, the behavior of a {@code Multimap} is not specified if key objects
 * already present in the multimap change in a manner that affects {@code equals} comparisons. Use
 * caution if mutable objects are used as keys in a {@code Multimap}.
 *
 * <p>All methods that modify the multimap are optional. The view collections returned by the

  protected Multimap<String, Integer> create() {
    Multimap<String, Integer> unfiltered = HashMultimap.create();
    unfiltered.put("foo", 55556);
    unfiltered.put("badkey", 1);
    return Multimaps.filterEntries(unfiltered, ENTRY_PREDICATE);
  }

  private static final Predicate<String> KEY_PREDICATE = key -> !Objects.equals(key, "badkey");

  public void testFilterKeys() {

 * already in the multimap has no effect. This interface does not specify the ordering of the
 * multimap's keys. See the {@link Multimap} documentation for information common to all multimaps.
 *
 * <p>The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods each return a {@link
 * SortedSet} of values, while {@link Multimap#entries()} returns a {@link Set} of map entries.

 * already in the multimap has no effect. This interface does not specify the ordering of the
 * multimap's keys. See the {@link Multimap} documentation for information common to all multimaps.
 *
 * <p>The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods each return a {@link
 * SortedSet} of values, while {@link Multimap#entries()} returns a {@link Set} of map entries.

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import org.jspecify.annotations.NullMarked;

/**
 * Test {@link Multimap#asMap()} for a {@link Multimaps#forMap} multimap with {@link
 * MapInterfaceTest}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public class ForMapMultimapAsMapImplementsMapTest extends AbstractMultimapAsMapImplementsMapTest {

   *
   * @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) {

   * Multimaps#asMap(ListMultimap)} instead.
   */
  @Override
  Map<K, Collection<V>> asMap();

  /**
   * Compares the specified object to this multimap for equality.
   *
   * <p>Two {@code ListMultimap} instances are equal if, for each key, they contain the same values
   * in the same order. If the value orderings disagree, the multimaps will not be considered equal.
   *