I think the Scala version does exactly what you want it to do, but you seem to be confused about something that I can't really pin-point. > Why do I need a sep

I think the Scala version does exactly what you want it to do, but you seem to be confused about something that I can't really pin-point. > Why do I need a separate Person and Dog class? You don't. It's an example. > Can't a dog have a name as well? It can. > Why do I need to declare that upfront or ensure that no other part of code can give a Dog a name? I have trouble understanding the meaning of that sentence.