input: 
  def sum_list_elements(data: List[int]) -> int:
      """ Given a list of integers, calculate the total sum of all elements in the list.
      >>> sum_list_elements([1, 9, 3, 5])
      18
      """
  
output:     total_sum = 0
      for num in data:
          total_sum += num
      return total_sum