input: Write a python function to find the maximum consecutive sum in an array.
  assert max_consecutive_sum([1, 2, 3, -2, 5]) == 9
  assert max_consecutive_sum([-1, -2, -3, -4]) == 0
  assert max_consecutive_sum([2, 3, -6, 4, 2, -1, 5, -3]) == 10
output: def max_consecutive_sum(arr):
      max_sum = 0
      current_sum = 0
      for num in arr:
          current_sum += num
          if current_sum < 0:
              current_sum = 0
          if current_sum > max_sum:
              max_sum = current_sum
      return max_sum