 
 class ViewController: UIViewController {
 
+//    可先用swiftyJSON 转化为JSON数据
+    
     override func viewDidLoad() {
         super.viewDidLoad()
 //        self.testAnimal()

           print(dog.xxx) // 随便来个属性，没值也不会报错 nil
        }
    }

}

extension ViewController {

         print(mouse.parent)
        }
    }
}

/* ============================模型类================================ */

class Animal: HandyJSON {
    var name: String?
