protected function findDetectionRulesAgainstUA(array $rules, $userAgent = null)
    {
        // Loop given rules
        foreach ($rules as $key => $regex) {
            if (empty($regex)) {
                continue;
            }

            // Check match
            if ($this->match($regex, $userAgent)) {
                return $key ?: reset($this->matchesArray);
            }
        }

        return false;
    }