Find the sum of all common divisors of 8 and 12.
8 [OP_LIST_GET_DIVISOR] 12 [OP_LIST_GET_DIVISOR] [OP_SET_INTERSECT] [OP_LIST_SUM]
var_a = 8
list_a = []
num_sqrt = int(math.sqrt(var_a))
for i in range(1, num_sqrt+1):
    if var_a % i == 0:
        list_a.append(i)
        list_a.append(int(var_a/i))
list_a = sorted(set(list_a))
var_b = 12
list_b = []
num_sqrt = int(math.sqrt(var_b))
for i in range(1, num_sqrt+1):
    if var_b % i == 0:
        list_b.append(i)
        list_b.append(int(var_b/i))
list_b = sorted(set(list_b))
list_c = list(set(list_a) & set(list_b))
list_c = [float(i) for i in list_c]
var_c = sum(list_c)
print(int(var_c))