Python - ayuda Python listas y strings

#!/usr/bin/env python

import re

from itertools import zip_longest

if __name__ == '__main__':

    string = 'a1b30c9d8e7f6g5h5i41j1k0l0m0n12'

    letters = re.findall('([A-Za-z])', string)

    numbers = re.findall('(\d+)', string)

    result = [[x, y] for x, y in zip_longest(letters, numbers, fillvalue=None)]

    print(result)

import re

string = 'a1b30c9d8e7f6g5h5i41j1k0l0m0n12'

print([list(m) for m in re.findall(r'(\D)(\d*)', string)])