input: Write a function to create a Python class called Rectangle that represents a two-dimensional rectangle with a length and width. The class should have an __init__ method to initialize the length and width, and an area method to calculate and return the area of the rectangle.
  
  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(2, 3).area()==6
  assert Rectangle(7, 7).area()==49
  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