secondVCWithNoPost.swift

class SecondVC: UIViewController {
  @IBOutlet weak var secondVCLabel: UILabel!
  
  override func viewDidLoad() {
    super.viewDidLoad()
    NotificationCenter.default.addObserver(self, 
                                           selector: #selector(doThisWhenNotify), 
                                           name: NSNotification.Name(rawValue: myNotificationKey), 
                                           object: nil)
  }
  
  func doThisWhenNotify() { print("I've sent a spark!") }
}