import static org.junit.Assert.assertThrows;

import com.google.common.collect.HashMultiset;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Multiset;
import com.google.common.collect.Ordering;
import com.google.common.primitives.Chars;
import org.jspecify.annotations.NullUnmarked;
import org.junit.Test;
import org.junit.runner.RunWith;

    suite.addTest(
        MultisetTestSuiteBuilder.using(
                new TestStringMultisetGenerator() {
                  @Override
                  protected Multiset<String> create(String[] elements) {
                    PopulatableMapAsMultimap<String, Integer> multimap =
                        PopulatableMapAsMultimap.create();

    suite.addTest(
        MultisetTestSuiteBuilder.using(
                new TestStringMultisetGenerator() {
                  @Override
                  protected Multiset<String> create(String[] elements) {
                    PopulatableMapAsMultimap<String, Integer> multimap =
                        PopulatableMapAsMultimap.create();

      public boolean remove(@Nullable Object o) { // for performance
        return !LinkedListMultimap.this.removeAll(o).isEmpty();
      }
    }
    return new KeySetImpl();
  }

  @Override
  Multiset<K> createKeys() {
    return new Multimaps.Keys<K, V>(this);
  }

  /**
   * {@inheritDoc}
   *
   * <p>The iterator generated by the returned collection traverses the values in the order they

    }
    return changed;
  }

  static boolean removeAllImpl(Set<?> set, Collection<?> collection) {
    checkNotNull(collection); // for GWT
    if (collection instanceof Multiset) {
      collection = ((Multiset<?>) collection).elementSet();
    }
    /*
     * AbstractSet.removeAll(List) has quadratic behavior if the list size
     * is just more than the set's size.  We augment the test by

   */
  public static <E> ImmutableSet<E> copyOf(Collection<? extends E> elements) {
    /*
     * TODO(lowasser): consider checking for ImmutableAsList here
     * TODO(lowasser): consider checking for Multiset here
     */
    // Don't refer to ImmutableSortedSet by name so it won't pull in all that code
    if (elements instanceof ImmutableSet && !(elements instanceof SortedSet)) {