Actually it's not important, I've updated the BaseService and forgot the Child ^^. In my projects I use 2 layers of abstraction: BaseService > ApiService > ChildA...Z. Inside ApiService (open class) I do have that method that can be overriden by ChildService with API error logic (BaseService should be agnostic). For this article I think 2 layers are enaught, that's why I missed that method. Thanks.

(code updated)