“make the foobar extensible” has no value without also “adding baz”. If I need to remove baz, I can’t just revert “adding baz”. The extensible foobar needs to g

“make the foobar extensible” has no value without also “adding baz”. If I need to remove baz, I can’t just revert “adding baz”. The extensible foobar needs to go as well because it’s a unused abstraction.