}

    @Override
    public @Nullable Entry<K, V> higherEntry(K key) {
      return standardHigherEntry(key);
    }

    @Override
    public @Nullable K higherKey(K key) {
      return standardHigherKey(key);
    }

    @Override
    public @Nullable Entry<K, V> firstEntry() {
      return standardFirstEntry();
    }

    /*

    }

    @Override
    public @Nullable Entry<K, V> higherEntry(K key) {
      return standardHigherEntry(key);
    }

    @Override
    public @Nullable K higherKey(K key) {
      return standardHigherKey(key);
    }

    @Override
    public @Nullable Entry<K, V> firstEntry() {
      return standardFirstEntry();
    }

    /*

   * {@code higherEntry}, you may wish to override {@code higherKey} to forward to this
   * implementation.
   */
  protected @Nullable K standardHigherKey(@ParametricNullness K key) {
    return keyOrNull(higherEntry(key));
  }

  @Override
  public @Nullable Entry<K, V> firstEntry() {
    return delegate().firstEntry();
  }

  /**

   * {@code higherEntry}, you may wish to override {@code higherKey} to forward to this
   * implementation.
   */
  protected @Nullable K standardHigherKey(@ParametricNullness K key) {
    return keyOrNull(higherEntry(key));
  }

  @Override
  public @Nullable Entry<K, V> firstEntry() {
    return delegate().firstEntry();
  }

  /**