As a user of your code, I'd find it a less pleasant API because I'd have to some_module.some_func.some_func() rather than just some_module.some_func()

No reason to have "some_func" exist twice in the hierarchy. It's kind of redundant. If some_func is so large that adding any more ocde to the file seems crazy, maybe some_func is too large and you want to refactor it and simplify it.

Having one file serve one purpose makes sense. Having it literally have only a single function and nothing else is pretty unusual.