code: func (api *API) OriginCertificates(options OriginCACertificateListOptions) ([]OriginCACertificate, error) {
  	v := url.Values{}
  	if options.ZoneID != "" {
  		v.Set("zone_id", options.ZoneID)
  	}
  	uri := "/certificates" + "?" + v.Encode()
  	res, err := api.makeRequestWithAuthType(context.TODO(), "GET", uri, nil, AuthUserService)
  
  	if err != nil {
  		return nil, errors.Wrap(err, errMakeRequestError)
  	}
  
  	var originResponse *originCACertificateResponseList
  
  	err = json.Unmarshal(res, &originResponse)
  
  	if err != nil {
  		return nil, errors.Wrap(err, errUnmarshalError)
  	}
  
  	if !originResponse.Success {
  		return nil, errors.New(errRequestNotSuccessful)
  	}
  
  	return originResponse.Result, nil
  }
docs: // OriginCertificates lists all Cloudflare-issued certificates.
  //
  // This function requires api.APIUserServiceKey be set to your Certificates API key.
  //
  // API reference: https://api.cloudflare.com/#cloudflare-ca-list-certificates