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