for::is

public function is($key, $userAgent = null, $httpHeaders = null)
    {
        // Set the UA and HTTP headers only if needed (eg. batch mode).
        if ($httpHeaders) {
            $this->setHttpHeaders($httpHeaders);
        }

        if ($userAgent) {
            $this->setUserAgent($userAgent);
        }

        $this->setDetectionType(self::DETECTION_TYPE_EXTENDED);

        return $this->matchUAAgainstKey($key);
    }