@Udf
  public <T extends Comparable<? super T>> List<T> arraySortDefault(@UdfParameter(
      description = "The array to sort") final List<T> input) {
    return arraySortWithDirection(input, "ASC");
  }
@Test
  public void shouldReturnNullForListOfNullInput() {
    final List<Integer> input = Arrays.asList(null, null, null);
    assertThat(udf.arraySortDefault(input),
        contains((Integer) null, (Integer) null, (Integer) null));
  }