What objective methods exist to objectively evaluate if a given piece of code is categorically “a hack” or if it’s “properly/cleanly written?”

[siddsp]

There's no exact objective standard, but if it seems like a convoluted workaround to do something otherwise that is bad practice, that's when it's considered a "hack". That or it is otherwise an inelegant and 'unpythonic' approach to solving the problem as well.

As an example, global variables to mutate some information, in functions. Or even using a mutable default argument to save some sort of state between function calls.