[Tutor] 'Right' way to implement mixins in Python?

[Kent Johnson]

On Wed, May 28, 2008 at 6:30 PM, Alan Gauld <alan.gauld at btinternet.com> wrote:

> Mixins should be as independant
> as possible from any other classes. Unfortunately thats not
> always possible so you should try to create an abstract
> superclass/interface and use that in your mixins. You can then
> subclass the mixin and replace the abstract class with the local
> concrete manifestation. It means one extra level of inheritance because
> you wind up with an abstract mixin plus the localised mixin.

I don't understand what you mean by this. Python doesn't really have
abstract classes and interfaces. And how is this different than
requiring the mixins to be used with only subclasses of a certain
concrete class?

> Instead build a protocol in the class framework outside the mixins
> and let them coerce the dependencies to suit the mixin interfaces.

Can you explain? I don't know what this means.

Thanks,
Kent