apply_method.scala

def apply(input: String): String = {
    val output = 
      Utils.read[SealedTraitParent](input) match {
        case Some(predict: Predict) => 
          println(predict)
          predict.process(client)
        case Some(train: Training) => 
          println(train)
          train.process(client)
        case None => 
          println(input)
          Right(new AlgorithmException(s"failed to parse"))
      }
    
    output match {
      case Left(result) => Utils.Write(result).nospaces
      case Right(err) => throw err
    }
  }