Hello Rubens, cool article!
Yannick Spark

Hi Yannick, thank for the feedback!

I’m far to be expert in the area too (I’m just a curious soul), but what I’ve understood is this isn’t a requirement, like Mr. Eric Elliott responded here to a similar question: https://medium.com/@_ericelliott/there-is-no-requirement-for-two-layers-of-wrapping-in-flatten-join-72b918a12dd3

What I’ve understood is, in your flatMap, If you lift at least one context your object will be already a monad. I’ll research more about multiple context liftings and if this categorize the Promises as a subtype of monads.