typealias OnComplete = (Result<String, Error>) -> Void
ResultSugarTests.assert(flag: true) { result in
   guard let msg: String = result.value() else { Swift.print("\(result.errorStr)"); return }
   Swift.print("\(msg)") // Works 👌
}
static func assert(flag: Bool, complete: OnComplete) {
  if flag {
     complete(.success("Works 👌"))
  } else {
     complete(.failure(NSError("Doesn't work 🚫")))
  }
}