zero_sum

def find_zero_sum(arr):
  sums = [0] * len(arr)
  for i, x in enumerate(arr):
    for j in range(0, i + 1): 
      sums[j] += arr[i]
      if sums[j] == 0:
        return (j, i)

arr = [8, 1, 2, 7, -4, -6]
zero_sum_index = find_zero_sum(arr) 
assert zero_sum_index == (1, 5)