class TKey:
    def __init__(self, x, compare):
        self.value = x
        self.cmp = compare

    def __le__(self, other):
        return self.cmp(self.value, other.value)

    def __lt__(self, other):
        return self <= other and self.value != other.value

    def __gt__(self, other):
        return not(self <= other)

    def __ge__(self, other):
        return not(self < other)


def main():
    straight_compare = lambda x, y: x <= y
    reverse_compare = lambda x, y: y <= x
    convert_to_key = lambda cmp: lambda x: TKey(x, cmp)
    print(sorted([1, 4, 35, 10, 8, 7, 9, 9, 12], key=convert_to_key(straight_compare))) # output: [1, 4, 7, 8, 9, 9, 10, 12, 35]
    print(sorted([1, 4, 35, 10, 8, 7, 9, 9, 12], key=convert_to_key(reverse_compare))) # output: [35, 12, 10, 9, 9, 8, 7, 4, 1]


main()