*/
  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)) {

    getMultiset().elementSet().clear();
    assertEmpty(getMultiset());
  }

  /**
   * Returns {@link Method} instances for the read tests that assume multisets support duplicates so
   * that the test of {@code Multisets.forSet()} can suppress them.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static List<Method> getElementSetDuplicateInitializingMethods() {
    return asList(

import static java.util.Collections.nCopies;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multiset.Entry;
import junit.framework.TestCase;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link Multisets#immutableEntry}.
 *
 * @author Mike Bostock
 */
@GwtCompatible
@NullMarked

    }
    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

    }
    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

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.features.CollectionFeature;
import java.util.Collections;
import org.junit.Ignore;

/**
 * Tests for {@code Multiset.add}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")

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;
import com.google.common.collect.RowSortedTable;

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;
import com.google.common.collect.RowSortedTable;

import com.google.common.collect.ImmutableTable;
import com.google.common.collect.ListMultimap;
import com.google.common.collect.MapDifference;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multiset;
import com.google.common.collect.PeekingIterator;
import com.google.common.collect.Range;
import com.google.common.collect.RowSortedTable;
import com.google.common.collect.SetMultimap;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.collect.Multiset.Entry;
import com.google.common.collect.Multisets.AbstractEntry;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Arrays;
import java.util.Objects;
import org.jspecify.annotations.NullMarked;