I'd say get ahold of animal control and see if they know of somebody who deals with them. I personally haven't had to deal with them (yet), but I've discussed it with neighbors who have and I've never heard of fumigating snakes, it's always been physical removal/killing.
Besides, even if you could fumigate, then you could end up with several (dozen?) dead snakes that will turn into rotting snakes.
Personally, I'd have no issue dealing with one snake in the open, but no way I'd screw with searching a house for them and then trying to clear them out.
IMO, that's just asking to get nailed and if you stumbled into a nest in the wrong place...