> If module global variables are considered truly horrible, the same can be said about instance variables inside classes. They are as good (or bad) as module globals in the sense that they represent shared state and can potentially be mutated by any method/member function in the class.

Assuming Python-like modules, module-level globals are worse for encapsulation.

1. A function can access module-level state without having been explicitly passed a reference to it.

2. You can't create additional instances of module-level state. For example, if your app server uses a module-level global for the server listening socket, you can't run two app server instances in the same process.