@Override
  public SelLong field(SelString field) {
    String fieldName = field.getInternalVal();
    if ("SUNDAY".equals(fieldName)) {
      return SelLong.of(DateTimeConstants.SUNDAY);
    }
    throw new UnsupportedOperationException(type() + " DO NOT support accessing field: " + field);
  }
@Test(expected = UnsupportedOperationException.class)
  public void testInvalidField() {
    SelLong res = SelMiscFunc.INSTANCE.field(SelString.of("Tomorrow"));
  }