input: 
  def area_of_rectangle(rectangle_length: float, rectangle_width: float) -> float:
      """ Calculate the area of a rectangle given its length and width.
      >>> area_of_rectangle(5.0, 3.0)
      15.0
      >>> area_of_rectangle(4.0, 4.0)
      16.0
      """
      return rectangle_length * rectangle_width
  
output:     return rectangle_length * rectangle_width