main.py

from functools import cmp_to_key

arr = [1, 2, 3, 4, 5]

def my_cmp(a, b):
    if a == b:
        return 0
    elif a < b:
        return -1
    else:
        return 1

arr.sort(key=cmp_to_key(my_cmp))

for k in arr:
    print(k)