I keep my cats and snakes separate. If I have a snake out in the same room as them for one reason or another, I try to maintain at least 5 or 10 feet between them, just because something COULD go wrong.
If you are going to have a large free-roaming pet around snake cages, make sure you observe behavior and interactions, and keep them separated when you can't observe, until you learn if you can trust them or not.