//Step1
extension Notification.Name {
    static let notifyName = Notification.Name("notifyName")
}

//Step2 Fire notify
NotificationCenter.default.post(name: .notifyName, object: nil)

//Step3 Add Observer
NotificationCenter.default.addObserver(self, selector: #selector(doSomething(_:)), name: .notifyName, object: nil)

//Step4 Do somthing
@objc func doSomething(_ notification: Notification)
    {
        print("doSomething")
    }

//Step4 Remove Observer
// すべて解除
center.removeObserver(self)
// 特定の通知のみ解除
center.removeObserver(self,
                      name: .UIApplicationDidBecomeActive,
                      object: nil)