I've recently come across a use of multiple inheritance in some python code that shows me why this is multiple inheritance is a bad thing. It seems to break the OOP concept of encapsulation.

With multiple inheritance you might be tempted to say the Pegasus extends Horse and Bird because you've classified the Bird as an animal with wings. However, Birds have other traits that Pegasi don't.

Multiple interface inheritance still allows an object to inherit methods and to behave polymorphically on those methods. The inheriting object just doesn’t get an implementation free ride.