}

  @Override
  public @Nullable Entry<E> firstEntry() {
    return isEmpty() ? null : getEntry(0);
  }

  @Override
  public @Nullable Entry<E> lastEntry() {
    return isEmpty() ? null : getEntry(length - 1);
  }

  @Override
  public int count(@Nullable Object element) {
    int index = elementSet.indexOf(element);
    return (index >= 0) ? getCount(index) : 0;

      return (entry == null) ? null : wrapEntry(entry);
    }

    @Override
    public @Nullable Entry<K, Collection<V>> lastEntry() {
      Entry<K, Collection<V>> entry = sortedMap().lastEntry();
      return (entry == null) ? null : wrapEntry(entry);
    }

    @Override
    public @Nullable Entry<K, Collection<V>> pollFirstEntry() {

     * @param map the sequenced map
     * @return the last entry, or null if the map is empty
     * @since Java 21
     */
    public static <K, V> Map.Entry<K, V> lastEntry(final SequencedMap<K, V> map) {
        return map.isEmpty() ? null : map.lastEntry();
    }

    /**
     * Returns a reversed view of a sequenced map.
     *
     * @param <K> the key type
     * @param <V> the value type