public void testPollLast() {
    assertEquals(c, navigableSet.pollLast());
    assertEquals(values.subList(0, values.size() - 1), Helpers.copyToList(navigableSet));
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  public void testPollLastUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> navigableSet.pollLast());
  }

  @CollectionSize.Require(SEVERAL)

        }
        return isRoot();
    }

    private boolean exitDirectory(Runnable exitDirectoryHandler) {
        if (directoryPaths.pollLast() == null) {
            return true;
        }
        if (directoryNames.pollLast() == null) {
            return true;
        }
        exitDirectoryHandler.run();
        return false;
    }

    return delegate.lower(checkValid(e));
  }

  @Override
  public @Nullable E pollFirst() {
    return delegate.pollFirst();
  }

  @Override
  public @Nullable E pollLast() {
    return delegate.pollLast();
  }

  @Override
  public boolean remove(Object object) {
    return delegate.remove(checkValid(object));
  }

  @Override
  public boolean removeAll(Collection<?> c) {

  }

  @Override
  @CheckForNull
  public E pollLast() {
    return delegate().pollLast();
  }

  /**
   * A sensible definition of {@link #pollLast} in terms of the {@code descendingIterator} method.
   * If you override {@link #descendingIterator} you may wish to override {@link #pollLast} to
   * forward to this implementation.
   */
  @CheckForNull

  }

  @Override
  @CheckForNull
  public E pollLast() {
    return delegate().pollLast();
  }

  /**
   * A sensible definition of {@link #pollLast} in terms of the {@code descendingIterator} method.
   * If you override {@link #descendingIterator} you may wish to override {@link #pollLast} to
   * forward to this implementation.
   */
  @CheckForNull

  public void testPollLast() {
    assertEquals(c, navigableSet.pollLast());
    assertEquals(values.subList(0, values.size() - 1), Helpers.copyToList(navigableSet));
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  public void testPollLastUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> navigableSet.pollLast());
  }

  @CollectionSize.Require(SEVERAL)

    return delegate().pollFirst(timeout, unit);
  }

  @Override
  @CheckForNull
  public E pollLast(long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().pollLast(timeout, unit);
  }

  @Override
  public void put(E e) throws InterruptedException {
    delegate().put(e);
  }

  @Override

    return delegate().pollFirst(timeout, unit);
  }

  @Override
  @CheckForNull
  public E pollLast(long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().pollLast(timeout, unit);
  }

  @Override
  public void put(E e) throws InterruptedException {
    delegate().put(e);
  }

  @Override

  @CheckForNull
  public E pollFirst() {
    return delegate().pollFirst();
  }

  @CanIgnoreReturnValue // TODO(cpovirk): Consider removing this?
  @Override
  @CheckForNull
  public E pollLast() {
    return delegate().pollLast();
  }

  @CanIgnoreReturnValue
  @Override
  @ParametricNullness
  public E pop() {
    return delegate().pop();
  }

  @Override

  @CheckForNull
  public E pollFirst() {
    return delegate().pollFirst();
  }

  @CanIgnoreReturnValue // TODO(cpovirk): Consider removing this?
  @Override
  @CheckForNull
  public E pollLast() {
    return delegate().pollLast();
  }

  @CanIgnoreReturnValue
  @Override
  @ParametricNullness
  public E pop() {
    return delegate().pop();
  }

  @Override