block4.swift

UNUserNotificationCenter.current().getNotificationSettings {
    (settings) in

    guard settings.authorizationStatus == .authorized else { return }

    let content = UNMutableNotificationContent()
    content.title = "Cat Title"
    content.subtitle = "Cat Subtitle"
    content.body = "Cat Body"
    content.sound = .default
    content.categoryIdentifier = "category-simple"

    let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 3, repeats: false)
    let uuid = UUID().uuidString
    let request = UNNotificationRequest(identifier: uuid, content: content, trigger: trigger)

    UNUserNotificationCenter.current().add(request, withCompletionHandler: {
        (error) in

    })
}