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 then print the average.
  assert calculate_average([2, 4, 6, 8, 10])==6.0
  assert calculate_average([1, 2, 3, 4, 5])==3.0
  assert calculate_average([-1, -2, -3, -4, -5])==-3.0
  assert calculate_average([0, 0, 0, 0, 0])==0.0
  assert calculate_average([100, 200, 300, 400, 500])==300.0
output: def calculate_average(numbers):
      return sum(numbers) / len(numbers)