input: def sum_list(input_list):
      """ Calculate the sum of items in the given list.
      >>> sum_list([1, 2, 3, 4])
      10
      >>> sum_list([0, -1, 1])
      0
      """
      sum = 0
      for i in input_list:
          sum += i
      return sum
output:     sum = 0
      for i in input_list:
          sum += i
      return sum