@Udf(description = "Returns all substrings of the input that matches the given regex pattern")
  public List<String> regexpExtractAll(
      @UdfParameter(description = "The regex pattern") final String pattern,
      @UdfParameter(description = "The input string to apply regex on") final String input
  ) {
    return regexpExtractAll(pattern, input, 0);
  }
@Test
  public void shouldReturnNullOnNullValue() {
    assertNull(udf.regexpExtractAll(null, null));
    assertNull(udf.regexpExtractAll(null, null, null));
    assertNull(udf.regexpExtractAll(null, "", 1));
    assertNull(udf.regexpExtractAll("some string", null, 1));
    assertNull(udf.regexpExtractAll("some string", "", null));
  }