To an extent that is what it ends up being 90% of the time given that a lot of the inheritance people use don't satisfy the LSP (Liskov Substitution Principle).

To an extent that is what it ends up being 90% of the time given that a lot of the inheritance people use don't satisfy the LSP (Liskov Substitution Principle). We've been using mypy with our python codebase and it will complain if you violate the LSP so much so that it prevents most inheritance. We mainly subclass for simple data models when it's a case of "every model has these 10 fields" and there are next to no methods on the data model classes.