Well that solves that mystery, I should have checked there lol.
I don't think that they are another type of leucism as they are not a completely white snake. they have yellows and grays. But I'm not well versed in Ivories or Leucistics
*Edit*
Now that I think about it maybe they are, they seem to come in blue eyed and black eyed versions. As I said I'm now well versed with white snakes.