input: Write a python function to find the first pair of indices where the elements sum to zero in a list.
  assert optimized_traverse([3, -1, 5, 7]) == None
  assert optimized_traverse([3, -1, 5, 7, -3]) == (0, 4)
  assert optimized_traverse([1, 2, 3, -2]) == (1, 3)
output: def optimized_traverse(lst):
      seen = {}
      for i, num in enumerate(lst):
          if -num in seen:
              return (seen[-num], i)
          seen[num] = i
      return None