public static function multiToAssocWithSpecificOpr(array $arrays, $opr = null)
    {
        $results = [];
        foreach ($arrays as $key => $value) {
            if (self::isReallyArray($value) === true) {
                $results = array_merge($results, self::multiToAssocWithSpecificOpr($value, $key.$opr));
            } else {
                $key = $opr.$key;
                $key = ($key[0] === '.' || $key[0] === '@' ? substr($key, 1) : $key);
                $results[$key] = $value;
            }
        }

        return $results;
    }