Google\Spreadsheet\DefaultServiceRequest::execute PHP Method

    protected function execute($ch)
    {
        $ret = curl_exec($ch);
        $info = curl_getinfo($ch);
        $httpCode = (int) $info["http_code"];
        if ($httpCode > 299) {
            switch ($httpCode) {
                case 401:
                    throw new UnauthorizedException("Access token is invalid", 401);
                    break;
                case 403:
                    throw new UnauthorizedException($ret, 403);
                    break;
                case 404:
                    throw new UnauthorizedException("You need permission", 404);
                    break;
                default:
                    throw new BadRequestException($ret, $info["http_code"]);
            }
        }
        curl_close($ch);
        return $ret;
    }