public function scoInfo($sco_id)
    {
        $response = $this->call('sco-info', array(
            'sco-id' => $sco_id,
        ));

        return array(
            'sco' => current($response->xpath('/results/sco')),
            'source-sco' => $response->xpath('/results/source-sco/source-sco'),
        );
    }