code: func (api *API) DeleteSSL(zoneID, certificateID string) error {
  	uri := "/zones/" + zoneID + "/custom_certificates/" + certificateID
  	if _, err := api.makeRequest("DELETE", uri, nil); err != nil {
  		return errors.Wrap(err, errMakeRequestError)
  	}
  	return nil
  }
docs: // DeleteSSL deletes a custom SSL certificate from the given zone.
  //
  // API reference: https://api.cloudflare.com/#custom-ssl-for-a-zone-delete-an-ssl-certificate