public function getContentDecisions($user_id, $content_id, $opts = array()) {
        $this->mergeArguments($opts, array(
            'account_id' => $this->account_id,
            'timeout' => $this->timeout
        ));

        $this->validateArgument($content_id, 'content id', 'string');

        $url = ($this->api_endpoint .
            '/v3/accounts/' . rawurlencode($opts['account_id']) .
            '/users/' . rawurlencode($user_id) .
            '/content/' . rawurlencode($content_id) .
            '/decisions');

        try {
            $request = new SiftRequest($url, SiftRequest::GET, $opts['timeout'], self::API3_VERSION,
                                       array('auth' => $this->api_key . ':'));
            return $request->send();
        } catch (Exception $e) {
            $this->logError($e->getMessage());
            return null;
        }
    }