input: def calculate_average(nums: List[int]) -> float:
      """ Calculate the average of a given list of five numbers.
      >>> calculate_average([1, 2, 3, 4, 5])
      3.0
      >>> calculate_average([10, 20, 30, 40, 50])
      30.0
      """
output:     return sum(nums) / len(nums)