input: 
  def sum_list(lst):
      """
      Calculates the sum of a given list of numbers.
  
      >>> sum_list([1, 2, 3, 4, 5])
      15
      """
      total = 0
      for num in lst:
          total += num
      return total
  
output:     total = 0
      for num in lst:
          total += num
      return total