private static void validateCharacterVal(
            ReadableConfig tableOptions, ConfigOption<String> option, boolean unescape) {
        if (tableOptions.getOptional(option).isPresent()) {
            final String value =
                    unescape
                            ? StringEscapeUtils.unescapeJava(tableOptions.get(option))
                            : tableOptions.get(option);
            if (value.length() != 1) {
                throw new ValidationException(
                        String.format(
                                "Option '%s.%s' must be a string with single character, but was: %s",
                                IDENTIFIER, option.key(), tableOptions.get(option)));
            }
        }
    }
Validates the option {@code option} value must be a Character.

@param tableOptions the table options
@param option       the config option
@param unescape     whether to unescape the option value
inlong-sort/sort-formats/format-rowdata/format-inlongmsg-rowdata-kv/src/main/java/org/apache/inlong/sort/formats/inlongmsgkv/InLongMsgKvFormatFactory.java