input: def Rectangle_Area(length: float, width: float) -> float:
      """Create a class Rectangle that represents a two-dimensional rectangle with a length and width.
      The class should have a method to calculate the area of the rectangle.
      >>> Rectangle_Area(5.0, 3.0)
      15.0
      >>> Rectangle_Area(10.0, 2.0)
      20.0
      """
output:     return length * width