Enumerating Oriented Gene Orderings (ROSALIND SIGN)

Given: A positive integer n≤6.

Return: The total number of signed permutations of length n, followed by a list of all such permutations (you may list the signed permutations in any order).

import copy
import math


def permutations(my_set, perm):
    if len(my_set) > 0:
        res = []
        for s in my_set:
            new_my_set = copy.deepcopy(my_set)
            new_my_set.remove(s)
            for j in permutations(new_my_set, perm + str(s)):
                res.append(j)
        return res
    else:
        return [perm]


def lenn_sets(my_set, res, k):
    if k > 1:
        new_res = []
        for r in range(len(res)):
            for i in my_set:
                new_res.append(res[r] + i)
        return lenn_sets(my_set, new_res, k-1)
    else:
        return res


n = 6r1 = permutations(list(range(1,n+1)), '')
my_set2 = ['+', '-']
r2 = lenn_sets(my_set2, copy.deepcopy(my_set2), n)
f = open('sign.txt', 'w')
f.write(str(int(math.factorial(n)*math.pow(2, n)))+'\n')
for r_1 in r1:
    for r_2 in r2:
        l = ''        for i in range(n):
            l += r_2[i] + r_1[i] + ' '        f.write(l.replace('+', '')+'\n')
f.close()