input: Write a function to prompt the user to enter the value of radius and calculate the area of a circle. The function should return the calculated area.
  
  def calculate_circle_area():
      Pi = 3.14
      radius = float(input("Please enter the radius of the circle: "))
      area = Pi * radius**2
      return area
  
  assert calculate_circle_area() == 3.14 * 1**2  # Assuming user inputs 1
  assert calculate_circle_area() == 3.14 * 2**2  # Assuming user inputs 2
  assert calculate_circle_area() == 3.14 * 3**2  # Assuming user inputs 3
  assert calculate_circle_area() == 3.14 * 5**2  # Assuming user inputs 5
  assert calculate_circle_area() == 3.14 * 0**2  # Assuming user inputs 0
output: def calculate_circle_area():
      Pi = 3.14
      radius = float(input("Please enter the radius of the circle: "))
      area = Pi * radius**2
      return area