Python sort list by function with two arguments

mysort_compare.py

import functools
from typing import List


class Solution(object):
    def largest_nums(self, nums: List[int]) -> str:
        snums = [str(item) for item in nums]
        snums.sort(key=functools.cmp_to_key(self.cmp), reverse=True)
        _res = ""
        for i in snums:
            _res += i
        return _res

    @staticmethod
    def cmp(s1, s2):
        s12 = s1 + s2
        s21 = s2 + s1
        if s12 < s21:
            return -1
        elif s12 > s21:
            return 1
        return 0
"""
# if you dont want use functools 
# https://stackoverflow.com/a/12749495
def make_comparator(less_than):
    def compare(x, y):
        if less_than(x, y):
            return -1
        elif less_than(y, x):
            return 1
        else:
            return 0
    return compare

"""


if __name__ == '__main__':
    solution = Solution()
    nums = [3, 30, 34, 5, 9]
    res = solution.largest_nums(nums)
    print(res)
   
"""
reference
https://stackoverflow.com/questions/49950997/python-sort-list-by-function-with-multiple-arguments
https://stackoverflow.com/questions/12749398/using-a-comparator-function-to-sort
"""