老师你好，我把计算年龄那块的代码单独写成一个函数，代入类型为UIDataPicker，代码如下:

func jisuanage(birthday:UIDatePicker) ->NSInteger{

        let gregorian = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)

        let now = NSDate()

       let components = gregorian?.components(NSCalendarUnit.YearCalendarUnit, fromDate:birthday.date, toDate: now, options: NSCalendarOptions(0))

        let age = components?.year

        return age!

    }

就没问题，但是如果把代入参数类型设置为NSData，然后代码改为：

 func jisuanage(birthdayyear:NSData) ->NSInteger{

        let gregorian = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)

        let now = NSDate()

        let components = gregorian?.components(NSCalendarUnit.YearCalendarUnit, fromDate:birthdayyear, toDate: now, options: NSCalendarOptions(0))

        let age = components?.year

        return age!

    }

就编译报错，报错内容：Extra argument 'toDate' in call，不知道是为什么，fromDate后面的参数不应该就是NSDate类型么？