private function normalize(array $matches) : array
    {
        $keys = $matches[1];
        $values = $matches[2];

        $return = [];

        foreach ($keys as $i => $key) {
            $key = strtolower(trim($key));

            if ($key == 'mode') {
                $value = strtolower($values[$i]);
            } else {
                $value = array_map(
                    function ($el) {
                        return trim($el, ', ');
                    },
                    explode(',', $values[$i])
                );
            }
            $return[$key] = $value;
        }

        return $return;
    }