input: def calculate_sum(arr):
      """
      Calculate the sum of the elements in a given array of integers.
      >>> calculate_sum([1, 3, 5, 7])
      16
      >>> calculate_sum([10, 20, 30])
      60
      """
      sum = 0
      for i in arr:
          sum += i
      return sum
output:     sum = 0
      for i in arr:
          sum += i
      return sum