That's been true for a very long while - in Python 2.1 (released just shy of 20 years ago), they added "new-style classes", class Foo(object), and for the entire life of Python 2 you weren't supposed to use "old-style classes", class Foo, because they behaved in confusing ways.

(Python 3 got rid of old-style classes and made the two syntaxes equivalent.)