result = Multisets.immutableEntry(result.getElement(), result.getCount());
      entryIterator.remove();
      return result;
    }
    return null;
  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {
    Iterator<Entry<E>> entryIterator = descendingEntryIterator();
    if (entryIterator.hasNext()) {
      Entry<E> result = entryIterator.next();

  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {
    return delegate().pollLastEntry();
  }

  /**
   * A sensible definition of {@link #pollLastEntry()} in terms of {@code
   * descendingMultiset().entrySet().iterator()}.
   *
   * <p>If you override {@link #descendingMultiset()} or {@link #entrySet()}, you may wish to
   * override {@link #pollLastEntry()} to forward to this implementation.
   */

  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {
    return delegate().pollLastEntry();
  }

  /**
   * A sensible definition of {@link #pollLastEntry()} in terms of {@code
   * descendingMultiset().entrySet().iterator()}.
   *
   * <p>If you override {@link #descendingMultiset()} or {@link #entrySet()}, you may wish to
   * override {@link #pollLastEntry()} to forward to this implementation.
   */

    }
    return result;
  }

  @Override
  public @Nullable Entry<E> pollFirstEntry() {
    return forwardMultiset().pollLastEntry();
  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {
    return forwardMultiset().pollFirstEntry();
  }

  @Override
  public SortedMultiset<E> headMultiset(E toElement, BoundType boundType) {

    return delegate().lastEntry();
  }

  @Override
  public @Nullable Entry<E> pollFirstEntry() {
    throw new UnsupportedOperationException();
  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {
    throw new UnsupportedOperationException();
  }

  @Override
  public SortedMultiset<E> headMultiset(@ParametricNullness E upperBound, BoundType boundType) {

      result = Multisets.immutableEntry(result.getElement(), result.getCount());
      entryIterator.remove();
      return result;
    }
    return null;
  }

  @Override
  public @Nullable Entry<E> pollLastEntry() {
    Iterator<Entry<E>> entryIterator = descendingEntryIterator();
    if (entryIterator.hasNext()) {
      Entry<E> result = entryIterator.next();

    public @Nullable E pollFirst() {
      return getElementOrNull(multiset().pollFirstEntry());
    }

    @Override
    public @Nullable E pollLast() {
      return getElementOrNull(multiset().pollLastEntry());
    }

    @Override
    public NavigableSet<E> subSet(
        @ParametricNullness E fromElement,
        boolean fromInclusive,
        @ParametricNullness E toElement,

    @Override
    public @Nullable Entry<K, Collection<V>> pollFirstEntry() {
      return pollAsMapEntry(entrySet().iterator());
    }

    @Override
    public @Nullable Entry<K, Collection<V>> pollLastEntry() {
      return pollAsMapEntry(descendingMap().entrySet().iterator());
    }

    @Nullable Entry<K, Collection<V>> pollAsMapEntry(
        Iterator<Entry<K, Collection<V>>> entryIterator) {