input: def Rectangle(length: float, width: float) -> str:
      """Create a Python class called Rectangle to represent a two-dimensional rectangle with a length and width.
      The class should have a method `area` that calculates and returns the area of the rectangle.
      >>> rect = Rectangle(5, 10)
      >>> rect.area()
      50
      >>> rect = Rectangle(3.5, 2.5)
      >>> rect.area()
      8.75
      """
output:     
  class Rectangle:
      def __init__(self, length: float, width: float):
          self.length = length
          self.width = width
  
      def area(self) -> float:
          return self.length * self.width
  