# 7.2Define a class named Shape and its subclass Square. The Square class has an init function which takes a length as argument. Both classes have a area function which can print the area of the shape where Shape's area is 0 by default.: class Shape(object):    def __init__(self):        pass    def area(self):        return 0class Square(Shape):    def __init__(self, l):        Shape.__init__(self)        self.length = l    def area(self):        return self.length*self.lengthaSquare= Square(3)print aSquare.area()