I cannot imagine how the banana gene would just somehow "super" or otherwise go crazy with the albino gene, unless they're somehow on the same loci and they're obviously not since banana het albinos are no more spectacular than non hets. Both genes just alter the pigment, that's it. The banana is a form of albinism that removes nearly all the pigment while the albino wipes it clean. Essentially, the albino would cover up the banana coloration, the result being a snake that is genetically albino and banana but only looks like a regular albino.