public static function ruleDate()
    {
        return function ($input) {
            $date = null;
            try {
                $date = date_parse($input);
                if ($date['warning_count'] === 0 && $date['error_count'] === 0) {
                    return strlen($date['hour']) === 0;
                }
                else {
                    return false;
                }
            }
            catch(\Exception $e) {
                return false;
            }
        };
    }