I'm working through the latest "Beginning iPhone Development with Swift" book. I noticed that in the "Fonts" project, there are two implementations of the "viewWillAppear" method: one for RootViewController and the other for FontListViewController. After typing in all the code and going back over it, to fully understand what is going on, I didn't understand the purpose of the implementation of this method for RootViewController and so I commented the method out to deactivate it. When I reran the code, I didn't notice a difference - everything worked just fine. I then went back into FontListViewController and did the same thing - deactivated the viewWillAppear method - and again, noticed that nothing changed in the app: the favorites section worked just as before with no issues.
Is this perhaps an issue with the simulator that I'm testing this out in, or is this some new behavior in the latest Xcode? I'm just confused at why this behavior would be observed when obviously the authors put the viewWillAppear implementation in there for a reason.