每天下午6点发送本地通知Swift 3 iOS 9

Question

我每天下午6点尝试在我的应用程序中触发本地通知。这是我正在使用的代码，但由于某些奇怪的原因，它并不想在特定时间触发。我做错了什么？

func notify() {

    let calendar: NSCalendar = NSCalendar(calendarIdentifier: .gregorian)!
    var dateFire=NSDate()

    var fireComponents=calendar.components([.month, .day, .hour, .minute], from:NSDate() as Date)

    fireComponents.hour = 18
    fireComponents.minute = 0

    dateFire = calendar.date(from: fireComponents)! as NSDate

    let notification = UILocalNotification()
    notification.alertBody = "Please take your tests for today! ❤️"
    notification.fireDate = fireDate // this always works NSDate().addingTimeInterval(0.0001) as Date
    notification.soundName = UILocalNotificationDefaultSoundName
    notification.repeatInterval = NSCalendar.Unit.day

    UIApplication.shared.scheduleLocalNotification(notification)
}

我也不想使用iOS 10中新的UserNotifications框架，因为我需要为iOS 9.0环境进行开发。