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 result. If the entered numbers are empty or less than five, the function should return None.
  
  def calculate_average():
      nums = []
      for i in range(5):
          nums.append(int(input("Please enter number: ")))
      if len(nums) < 5:
          return None
      average = sum(nums) / len(nums)
      print("The average is ", average)
  
  assert calculate_average()!=None
  assert calculate_average()!=None
  assert calculate_average()!=None
  assert calculate_average()!=None
  assert calculate_average()!=None
output: def calculate_average():
      nums = []
      for i in range(5):
          nums.append(int(input("Please enter number: ")))
      if len(nums) < 5:
          return None
      average = sum(nums) / len(nums)
      print("The average is ", average)