Correctly using a language feature often means using it for more than one reason. Extending superclass code can be well advised in case it also makes sense sema

Correctly using a language feature often means using it for more than one reason. Extending superclass code can be well advised in case it also makes sense semantically. Now, I have seen a "mixin" class that just served to provide one relatively independent method, and I turned it into a free function. Much better. In other cases, an extended class works on the whole state of the object. In that case it usually makes sense.