我正在尝试创建一个字典，我可以将其制作成JSON格式的对象并发送到服务器。例子:varusers=[["First":"Albert","Last":"Einstein","Address":["Street":"112MercerStreet","City":"Princeton"]],["First":"Marie","Last":"Curie","Address":["Street":"108boulevardKellermann","City":"Paris"]]]我用这个功能funcnsobjectToJSON(swiftObject:NSObject)->NSString{