assertTrue(Thread.holdsLock(mutex));
      return super.replaceValues(key, values);
    }

    @Override
    public boolean remove(@Nullable Object key, @Nullable Object value) {
      assertTrue(Thread.holdsLock(mutex));
      return super.remove(key, value);
    }

    @Override
    public Set<V> removeAll(@Nullable Object key) {
      assertTrue(Thread.holdsLock(mutex));

    }
  }

  /**
   * Delegates to {@link Collection#remove}. Returns {@code false} if the {@code remove} method
   * throws a {@code ClassCastException} or {@code NullPointerException}.
   */
  static boolean safeRemove(Collection<?> collection, @CheckForNull Object object) {
    checkNotNull(collection);
    try {
      return collection.remove(object);
    } catch (ClassCastException | NullPointerException e) {

      remaining--;
      return output(entry);
    }

    @Override
    public void remove() {
      if (modCount != expectedModCount) {
        throw new ConcurrentModificationException();
      }
      if (toRemove == null) {
        throw new IllegalStateException("no calls to next() since the last call to remove()");
      }
      delete(toRemove);
      expectedModCount = modCount;
      toRemove = null;

   * {@link SortedMultiset#tailMultiset}, the {@code size()} and {@code iterator()} methods of
   * {@link SortedMultiset#entrySet}, and {@link SortedMultiset#remove(Object, int)}. In many
   * situations, you may wish to override {@link SortedMultiset#elementSet} to forward to this
   * implementation or a subclass thereof.
   */

    if (entryIterator.hasNext()) {
      Entry<E> result = entryIterator.next();
      result = Multisets.immutableEntry(result.getElement(), result.getCount());
      entryIterator.remove();
      return result;
    }
    return null;
  }

  @Override
  @CheckForNull
  public Entry<E> pollLastEntry() {
    Iterator<Entry<E>> entryIterator = descendingEntryIterator();

    }
  }

  private static Set<Feature<?>> computeReserializedCollectionFeatures(Set<Feature<?>> features) {
    Set<Feature<?>> derivedFeatures = new HashSet<>(features);
    derivedFeatures.remove(SERIALIZABLE);
    derivedFeatures.remove(SERIALIZABLE_INCLUDING_VIEWS);
    return derivedFeatures;
  }

  public void testRemove_occurrences_negative() {
    try {
      getMultiset().remove(e0(), -1);
      fail("multiset.remove(E, -1) didn't throw an exception");
    } catch (IllegalArgumentException required) {
    }
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRemove_occurrences_wrongType() {
    assertEquals(
        "multiset.remove(wrongType, 1) didn't return 0",
        0,

    // no entry
    assertEquals(0, segment.count);
    assertNull(segment.remove(key, hash));
    assertEquals(0, segment.count);

    // same key
    segment.setTableEntryForTesting(index, entry);
    segment.count++;
    assertEquals(1, segment.count);
    assertSame(oldValue, segment.get(key, hash));
    assertSame(oldValue, segment.remove(key, hash));
    assertEquals(0, segment.count);

    // no entry
    assertEquals(0, segment.count);
    assertNull(segment.remove(key, hash));
    assertEquals(0, segment.count);

    // same key
    segment.setTableEntryForTesting(index, entry);
    segment.count++;
    assertEquals(1, segment.count);
    assertSame(oldValue, segment.get(key, hash));
    assertSame(oldValue, segment.remove(key, hash));
    assertEquals(0, segment.count);

    checkNotNull(node, "node");

    GraphConnections<N, V> connections = nodeConnections.get(node);
    if (connections == null) {
      return false;
    }

    if (allowsSelfLoops()) {
      // Remove self-loop (if any) first, so we don't get CME while removing incident edges.
      if (connections.removeSuccessor(node) != null) {
        connections.removePredecessor(node);
        --edgeCount;
      }
    }