public function getCurlBaseOpts()
 {
     $opts = parent::getCurlBaseOpts();
     if ($this->isCertificateAuthentication()) {
         $opts[CURLOPT_SSLCERTTYPE] = 'PEM';
         $opts[CURLOPT_SSLCERT] = $this->account_config['CertificatePath'];
     }
     return $opts;
 }