input: from typing import List
  
  
  def Rectangle_Areas(rectangles: List[Rectangle]) -> List[float]:
      """ Given a list of Rectangle objects, return a list of their areas.
      >>> rect1 = Rectangle(4, 5)
      >>> rect2 = Rectangle(3, 3)
      >>> Rectangle_Areas([rect1, rect2])
      [20, 9]
      """
      
  class Rectangle:
      def __init__(self, length, width):
          self.length = length
          self.width = width
  
      def area(self):
          return self.length * self.width
output:     return [rect.area() for rect in rectangles]