@Udf(description = "Returns the sign of an INT value, denoted by 1, 0 or -1.")
  public Integer sign(
      @UdfParameter(
          value = "value",
          description = "The value to get the sign of."
      ) final Integer value
  ) {
    return value == null
        ? null
        : Integer.signum(value);
  }
@Test
  public void shouldHandleNull() {
    assertThat(udf.sign((Integer)null), is(nullValue()));
    assertThat(udf.sign((Long)null), is(nullValue()));
    assertThat(udf.sign((Double)null), is(nullValue()));
  }