Returning the Pair of numbers whose sum is the closest to zero

from itertools import permutations as perm

def closest_to_zero(arr):
    L1, D1, found = perm(arr, 2), dict(), False

    for i in L1:
        D1[sum(i)] = i

    L2 = [abs(i) for i in D1.keys()]
    req_val = min(L2)

    while not found:
        res_T1 = D1.get(req_val, "")
        if any(res_T1):
            return res_T1
        else:
            req_val = -req_val

    return res_T1

var = closest_to_zero([10,20,30,40,50,60,-1,-2,-3,-4,-5,-6])
print(var)