ex2 - https://medium.com/@lu4nm3/monad-transformers-vs-mtl-d3a1167e2649

ex2_mvm.scala

val getJobStatus: Config => IO[Status] = ???
def sendAlert(status: Status): Config => IO[Unit] = ???

// ReaderT[F[_], E, A] is a type alias of Kleisli[F, E, A] so we can use the Kleisli constructor to wrap our functions
val getJobStatusR: ReaderT[IO, Config, Status] = Kleisli(getJobStatus)
def sendAlertR(status: Status): ReaderT[IO, Config, Unit] = Kleisli(sendEmail(status))

val program: ReaderT[IO, Config, Unit] = for {
  status <- getJobStatusR
  _ <- sendAlertR(status, user)
} yield ()

program.run(Config("127.0.0.1:8080")) // IO[Unit]