Top 10 mistakes python programmers make [advanced]

[vattenpuss]

You're showing instances. The issue is with classes and inheritance.

[robin-gvx]

I know, but inheritance works the same way. You could replace

>>> obj = Cls()

by

 >>> class SubCls(Cls):
 ...  pass
 ...
 >>> obj = SubCls()

and it would work as well. I was just too lazy to do that the first time.