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