All permutations of a Windows license key

Disclaimer: Yes, I know that this is not Python code. It just popped into my mind and I simply had to write it down.

The simplest way is the use of shell expansion:

$ echo MPP6R-09RXG-2H{8,B}MT-{B,8}K{H,N}M9-V{6,G}C8RMPP6R-09RXG-2H8MT-BKHM9-V6C8RMPP6R-09RXG-2H8MT-BKHM9-VGC8RMPP6R-09RXG-2H8MT-BKNM9-V6C8RMPP6R-09RXG-2H8MT-BKNM9-VGC8RMPP6R-09RXG-2H8MT-8KHM9-V6C8RMPP6R-09RXG-2H8MT-8KHM9-VGC8RMPP6R-09RXG-2H8MT-8KNM9-V6C8RMPP6R-09RXG-2H8MT-8KNM9-VGC8RMPP6R-09RXG-2HBMT-BKHM9-V6C8RMPP6R-09RXG-2HBMT-BKHM9-VGC8RMPP6R-09RXG-2HBMT-BKNM9-V6C8RMPP6R-09RXG-2HBMT-BKNM9-VGC8RMPP6R-09RXG-2HBMT-8KHM9-V6C8RMPP6R-09RXG-2HBMT-8KHM9-VGC8RMPP6R-09RXG-2HBMT-8KNM9-V6C8RMPP6R-09RXG-2HBMT-8KNM9-VGC8R

from itertools import productfor perm in product('8B', 'B8', 'HN', '6G'):    print 'MPP6R-09RXG-2H%sMT-%sK%sM9-V%sC8R' % perm

Another way to generate the combinations

>>> ['MPP6R-09RXG-2H%sMT-%sK%sM9-V%sC8R' % (a, b, c, d)...  for a in '8B' for b in 'B8' for c in 'HN' for d in '6G']['MPP6R-09RXG-2H8MT-BKHM9-V6C8R', 'MPP6R-09RXG-2H8MT-BKHM9-VGC8R', 'MPP6R-09RXG-2H8MT-BKNM9-V6C8R', 'MPP6R-09RXG-2H8MT-BKNM9-VGC8R', 'MPP6R-09RXG-2H8MT-8KHM9-V6C8R', 'MPP6R-09RXG-2H8MT-8KHM9-VGC8R', 'MPP6R-09RXG-2H8MT-8KNM9-V6C8R', 'MPP6R-09RXG-2H8MT-8KNM9-VGC8R', 'MPP6R-09RXG-2HBMT-BKHM9-V6C8R', 'MPP6R-09RXG-2HBMT-BKHM9-VGC8R', 'MPP6R-09RXG-2HBMT-BKNM9-V6C8R', 'MPP6R-09RXG-2HBMT-BKNM9-VGC8R', 'MPP6R-09RXG-2HBMT-8KHM9-V6C8R', 'MPP6R-09RXG-2HBMT-8KHM9-VGC8R', 'MPP6R-09RXG-2HBMT-8KNM9-V6C8R', 'MPP6R-09RXG-2HBMT-8KNM9-VGC8R']>>>