AppUpdateChecker().conferm() {
    result in
    switch result {
    case .existUpdate(let version, let storeScheme):
        // For example, Show UIAlertController here.
        print("Now available version: \(version)")
        print("DL from hare: \(storeScheme.absoluteString)")
    case .noUpdate:
        print("Current version is newest")
    case .error(let error):
        print("error: \(error)")
    }
}