The milk snake will literally kill your ball python. The end done. It will then probably try and eat the ball python and subsequently die because the ball python is too large to digest.
Its a terrible idea and if you do it then you deserve any problems that come your way.
You'll have a hard time convincing even me who isn't totally against keeping two snakes of the same species together, to even keep those two snakes together.
However two snakes of different species? Completely different genus and family? Even worse.
Don't do it because it's stupid and borderline animal abuse.
Also, both milk snakes and ball pythons are nocturnal.
