Call can throw but it is not marked with try

错误原因：

let dic =  NSJSONSerialization.JSONObjectWithData(datas!, options: .MutableContainers)

正确写法:
        do {
                let jsonData = try NSJSONSerialization.JSONObjectWithData(datas!, options: .MutableContainers)
                print(jsonData)
               
            } catch {
               
            }