def zeroOnArithmeticException(x: Future[Int]): Future[Int] = {
    val p = promise[Int]
    x onSuccess {
      case luku => p.trySuccess(luku)
    }
    x onFailure {
      case failure => failure match{
        case e: ArithmeticException => p.tryCompleteWith(future(0))
        case muut => p.tryFailure(muut)
      }
    }
    p.future
  }