public static function setPluralRule(callable $rule, $language)
    {
        // temporary set a language for brazilian
        if ("pt_BR" == $language) {
            $language = "xbr";
        }

        if (strlen($language) > 3) {
            $language = substr($language, 0, -strlen(strrchr($language, '_')));
        }

        if (!is_callable($rule)) {
            throw new \LogicException('The given rule can not be called');
        }

        self::$position_rules[$language] = $rule;
    }