Stalls out at check 11.

I'm getting a fail after check 11 on this one.

It shows:

Your result: 90177535 Pass Checkio(19)

I'm assuming I'm failing the 12th check, but there's no message which states:

Your answer : Correct answer:

Here's my code.

import itertools

def sum_list(l):
    result =0
    for x in range(len(l)):
        result += sum(l[x])
    return result 

def make_comb (com_list):
    combs = []
    for i in range(1, len(com_list)+1):
        l = [list(x) for x in itertools.combinations(com_list, i)]
        combs.extend(l)

    return combs

def checkio(data):

    base_list = list(range(1,data+1))
    change_list = base_list
    combs =[]
    final = 0

    for i in reversed(range(1,data+1)):

        combs  = make_comb(change_list)
        final += sum_list(combs)
        change_list.remove(i)

    #print (combs)
    return final