input: Write a function to create a Python class called Rectangle to represent a two-dimensional rectangle with a length and width. The class should include an __init__ method to initialize the length and width, and an area method that returns the area of the rectangle.
  
  assert Rectangle(4, 5).area() == 20
  assert Rectangle(3, 3).area() == 9
  assert Rectangle(1, 6).area() == 6
  assert Rectangle(0, 0).area() == 0
  assert Rectangle(2, 7).area() == 14
output: class Rectangle:
      def __init__(self, length, width):
          self.length = length
          self.width = width
      
      def area(self):
          return self.length * self.width