protected function mapper(string $key)
    {
        $character = $this->getOption('character');
        $config = config('mentions.pools.' . $this->getOption('pool'));

        $mention = str_replace($character, '', trim($key));

        $mentionned = $config['model']::whereRaw("LOWER({$config['column']}) = ?", [Str::lower($mention)])->first();

        if ($mentionned == false) {
            return null;
        }

        if ($this->getOption('mention') == true && $mentionned->getKey() !== Auth::id()) {
            $this->model->mention($mentionned, $this->getOption('notify'));
        }

        return '/' . preg_quote($key) . '(?!\w)/';
    }