class A: ... class A(metaclass=type): ... class A( metaclass=type ): ... class A( metaclass=type # ): ... class A( # metaclass=type ): ... class A( metaclass=type, # ): ... class A( # metaclass=type, # ): ... class B(A, metaclass=type): ... class B( A, metaclass=type, ): ... class B( A, # comment metaclass=type, ): ... def foo(): class A(metaclass=type): ... class A( metaclass=type # comment , ): ... type = str class Foo(metaclass=type): ... import builtins class A(metaclass=builtins.type): ...