Extensions in #swift are great, they allow you to reuse code and put it where it makes the most sense.
This one encapsulates the functionality of adding and removing embedded child view controllers in order to have more modular and independent interfaces.
Sometimes it's hard to manage all the topics and skills you're learning as a #developer at the same time. For that reason, I think using #PersonalKanban principles is a very useful way to manage this complexity in a more visual way.