public <T extends SELF> T setParam(String key, @Nullable String value) {
    return (T) setSingleValueParam(key, value);
  }
@Test
  public void skip_null_value_in_multi_param() {
    underTest.setParam("key", asList("v1", null, "", "v3"));

    assertMultiValueParameters(entry("key", asList("v1", "", "v3")));
  }