Nicholas Matthews added the comment: Thanks for the clarification. For the first point on the correctness of the original text, that makes sense, could you link me to any relevant documentation for further reading? On the second point "Meta modifies the creation of the classes themselves, not instances of the classes." I think this is not 100% correct. When you create an instance of a class via "instance = MyClass()", the `__call__` method of the metaclass is invoked, so metaclasses can control both class definition and instance creation. ---------- _______________________________________ Python tracker https://bugs.python.org/issue36947 _______________________________________