input: def calculate_average(list_of_positive_integers: List[int]) -> float:
      """ Calculate the average of a list of positive integers and output the result.
      >>> calculate_average([1, 5, 6, 7, 8])
      5.4
      """
output:     if not list_of_positive_integers:
          return 0.0
      total_sum = sum(list_of_positive_integers)
      count = len(list_of_positive_integers)
      return total_sum / count