Mark, please calm down. Modules are incredibly simple objects compared to classes -- and yet you can change the __class__ of a class. You can also directly modify the __dict__ of a module. You can shoot yourself in the foot phenomenally this way, but that's not the point. The point is not to violate *internal* constraints of the interpreter. Changing immutable objects was violating such a constraint. Changing a module's __class__ is not.