input: 
  def calculate_circle_area():
      """ Prompts the user to enter the value of radius to calculate the area of a circle.
      >>> calculate_circle_area()
      Please enter the radius of the circle: 5.0
      The area of the circle is: 78.5
      """
      Pi = 3.14
      radius = float(input("Please enter the radius of the circle: "))
      area = Pi * radius ** 2
      print("The area of the circle is:", area)
  
output:     Pi = 3.14
      radius = float(input("Please enter the radius of the circle: "))
      area = Pi * radius ** 2
      print("The area of the circle is:", area)