.get(stream -> stream.filter(StringUtil::isNotBlank).map(String::trim).filter(s -> isNonEmptyValue(source.get(s)))
                        .filter(s -> !validateDateTimeString(source.get(s))).collect(Collectors.toList()));
    }

    default boolean validateDateTimeString(final Object obj) {
        if (FessFunctions.parseDate(obj.toString()) != null) {
            return true;
        }
        return false;
    }