input: Write a function to determine if it is possible to create an instance of the Rectangle class and calculate its area correctly. The Rectangle class should be defined with a constructor that takes two parameters (length and width) and a method to calculate the area.
  assert Rectangle(4, 5).area()==20
  assert Rectangle(3, 7).area()==21
  assert Rectangle(10, 2).area()==20
  assert Rectangle(6, 8).area()==48
  assert Rectangle(0, 5).area()==0
output: class Rectangle:
      def __init__(self, length, width):
          self.length = length
          self.width = width
      
      def area(self):
          return self.length * self.width