This can be a tricky subject to get right. What I found useful for this aspect of functional programming was having to implement a new monad as the result of a

This can be a tricky subject to get right. What I found useful for this aspect of functional programming was having to implement a new monad as the result of a real engineering exercise. https://sambernheim.com/blog/building-a-monad https://sambernheim.com/blog/building-a-monad This goes through a real problem with various solutions that evolve to support additional requirements and results in the design of a new Monad