Haskell Monads - The List Monad

This topic is for the [The List Monad] exercise in the [Haskell Monads] trail. Post any questions, corrections, or pointers you have to share with other Upcase subscribers.
[The List Monad]: https://exercises.upcase.com/exercises/the-list-monad
[Haskell Monads]: Haskell Monads | Online Tutorial by thoughtbot