@Override
  public T pollLast()
  {
    if (_tail == null)
    {
      return null;
    }
    return removeNode(_tail);
  }
@Test
  public void testPollLast()
  {
    List<Integer> control = new ArrayList<>(Arrays.asList(1, 2, 3));
    LinkedDeque<Integer> q = new LinkedDeque<>(control);

    Assert.assertEquals(q.pollLast(), control.remove(control.size() - 1));
    Assert.assertEquals(q, control);
  }