code: public OvhOrder vps_serviceName_upgrade_duration_GET(String serviceName, String duration, String model) throws IOException {
  		String qPath = "/order/vps/{serviceName}/upgrade/{duration}";
  		StringBuilder sb = path(qPath, serviceName, duration);
  		query(sb, "model", model);
  		String resp = exec(qPath, "GET", sb.toString(), null);
  		return convertTo(resp, OvhOrder.class);
  	}
docs: Get prices and contracts information
  
  REST: GET /order/vps/{serviceName}/upgrade/{duration}
  @param model [required] Model
  @param serviceName [required] The internal name of your VPS offer
  @param duration [required] Duration