... away, because they are not part of the API of the service and we don’t want any other object, now or in the future, to become coupled to them (the way they work or even that they exist at all). ... ask the question, “When working on a system that is one to two years old and you need to add a new func-tion, there is effort to write the function and then effort to integrate it into the ... a bit further and going back to the testability issue, we might start pulling one or more of these behaviors out, to make them testable, and in so doing discover opportunities for the Strategy...