     ///  获取模型信息
     ///
     ///  :param: cls 模型类
-    func modelInfo(cls: AnyClass) -> Dictionary<String, AnyObject?> {
+    func modelInfo(cls: AnyClass) -> Dictionary<String, AnyObject> {
         
         if let cache = cacheModel(cls) {
             return cache

                value = NSNull()
            }
            
            if customClass == nil || value === NSNull() {
                infoDict[key] = value
            } else {
                let type = NSStringFromClass(value!.classForCoder)

        for (key, customClass) in modelInfo {
            // 如果赋值字典中存在内容
            if let value: AnyObject = dict[key] {
                if customClass === NSNull() && !(value === NSNull()) {
                    obj.setValue(value, forKey: key)
                } else {
                    let type = NSStringFromClass(value.classForCoder)
