input: from typing import List
  
  
  def calculate_average_of_five_numbers(nums: List[int]) -> float:
      """ Calculates the average of five numbers entered by a user.
      >>> calculate_average_of_five_numbers([10, 20, 30, 40, 50])
      30.0
      >>> calculate_average_of_five_numbers([1, 2, 3, 4, 5])
      3.0
      """
  
output:     if len(nums) != 5:
          raise ValueError("The list must contain exactly five numbers.")
      return sum(nums) / 5