input: Write a function to prompt the user to enter the value of the radius and calculate the area of a circle.
  def calculate_circle_area():
      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)
  assert calculate_circle_area() == None
output: def calculate_circle_area():
      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)