object Tasks sealed trait Minor def period Duration sealed trait Major

object Tasks {

  sealed trait Minor {
    def period: Duration
  }
  sealed trait Major

  sealed trait Task {
    def majorParams: Major
    def minorParams: Minor
  }

  case class CheckInventory(majorParams: CheckInventoryMajor, minorParams: CheckInventoryMinor) extends Task
  case class CheckInventoryMinor(period: Duration) extends Minor
  case class CheckInventoryMajor(user: User) extends Major

}