input: Write a function to create a Python class called Rectangle that represents a two-dimensional rectangle with a length and width, and includes a method to calculate its area.
  
  class Rectangle:
      def __init__(self, length, width):
          self.length = length
          self.width = width
  
      def area(self):
          return self.length * self.width
  
  assert Rectangle(5, 10).area() == 50
  assert Rectangle(3, 3).area() == 9
  assert Rectangle(0, 7).area() == 0
  assert Rectangle(2, 4).area() == 8
  assert Rectangle(1, 1).area() == 1
output: class Rectangle:
      def __init__(self, length, width):
          self.length = length
          self.width = width
  
      def area(self):
          return self.length * self.width