Am not 100% sure a cat would be stupid enough to even bother sniffing a sleeping python...luckily they're pretty still when their not eating.

I've lost 2 dogs to snakes, but never a cat....but I'd probably wait a few hours for snakey to move on. However, if he looked like he's digesting a feed I would let kitty out, becuase snake is pretty much going to do nothing! :-D