class Foo: pass class Bar(Foo): pass class Baz(Bar): pass class XXX: pass class Frob(Baz,XXX): pass print issubclass(Bar,Foo) print issubclass(Foo,Bar) print issubclass(Baz,Foo) print issubclass(Baz,Bar) print issubclass(Foo,object) print issubclass(Frob,XXX)