#8 is pretty great in that you can assign methods to custom types but not builtins. As an example, say I have []Card. If I want to sum all cards with a certain

#8 is pretty great in that you can assign methods to custom types but not builtins. As an example, say I have []Card. If I want to sum all cards with a certain color then I could Sum(cards []Card, color string) but that is not great. Rather, I could use type Cards []Card and then name a method (cards *Cards) Sum(color string) int The benefit is that any []Card can now have Sum called on it without any explicit casting. I've been using this and find it to be clean.