input: Write a function to calculate the average of five numbers entered by a user. The function should prompt the user to input five numbers, calculate their average, and return the result as a float. If the input is less than five numbers, raise a ValueError.
  assert calculate_average([1, 2, 3, 4, 5]) == 3.0
  assert calculate_average([10, 20, 30, 40, 50]) == 30.0
  assert calculate_average([0, 0, 0, 0, 0]) == 0.0
  assert calculate_average([-1, -2, -3, -4, -5]) == -3.0
  assert calculate_average([5, 10, 15, 20, 25]) == 15.0
output: def calculate_average(numbers):
      if len(numbers) != 5:
          raise ValueError("Input must be exactly five numbers")
      return sum(numbers) / 5.0