- (instancetype) initWithDict:(NSDictionary *)dict

{

    if (self = [super init]) {

        self.answer = dict[@"answer"];

        self.title = dict[@"title"];

        self.icon = dict[@"icon"];

        self.questions = dict[@"questions"];

    }

    return self;

}

+ (instancetype) questionWithDict:(NSDictionary *)dict

{

    return [[self alloc] initWithDict:dict];

}

一般类的初始化方法