Yeah, DNA "testing" is relatively cheap these days. I work in a lab where we're currently using map-based cloning to clone a gene in Medicago truncatula and running reactions, getting DNA sequence, etc just isn't that expensive now a days. But the problem with screening ball pythons (or other snakes) is that I can't think of a reason to do so other than scientific curiosity. Which unless there is a possible eventual benefit for people; it often doesn't get funded.