gustavofranke

object Fintech5 {
    data class ValidationError(val message: String)

    data class CreatePortfolio(val userId: String, val amount: Double)
    data class ChangePortfolio(val userId: String, val stock: String, val quantity: Int)

    interface Validator<T> {
        fun T.check(): EitherNel<ValidationError, T>
    }