input: def calculate_factorial(n):
      """
      Write a recursive function to calculate the factorial of a given number.
      >>> calculate_factorial(5)
      120
      >>> calculate_factorial(3)
      6
      """
      if n == 1:
          return 1
      else:
          return n * calculate_factorial(n - 1)
output:     if n == 1:
          return 1
      else:
          return n * calculate_factorial(n - 1)