What everyone else said.
As for genes "canceling out," they shouldn't. Let's use Greg's example of a Dreamsicle Stripe x Ghost Clown. If we have a Dreamsicle Stripe, we know those genes don't cancel, and if we have a Ghost Clown, we know those don't either. Similarly, all the other combinations don't cancel either: Pied Stripes, Lavender Stripes, Ghost Stripes, Ghost Pieds, Ghost Lavs, Lav Clowns, Stripe Clowns, Pied Clowns. So a snake with all of these genes would show all of these recessive traits without any cancellations.
Look at corn snakes. They have all kinds of multiple-recessive-gene morphs out there!
The reason we don't see many triple+ hets out there is because 1) ball pythons don't have as many offspring as corn snakes, so it takes longer and 2) double recessives are still pretty rare/expensive. Very few people have double recessives to breed to other single/double recessives, and the people who do are probably keeping all the offspring.
There are genes that suppress/dominate others, but I doubt any outright cancel them (i.e. make the genes nonexistent when they shouldn't be). Leucistics, for example, suppress pattern and color, but existing pattern/color genes are still present in the snake. Leucistics still have normal genes in there, too, but the leucism suppresses them (i.e., makes them not visible). In that sense, all morphs suppress the "normal" genes.
Does that kinda make sense?