Object Oriented Python - rectangle using classes and functions

I am creating a program in Python that will utilize object oriented programming to print the properties of a given rectangle. The project has these given constraints:

The purpose of this lab is to give you practice creating your own object. You will be given a main function that expects an instance of the (yet undefined) Rectangle object. Your job is to determine what attributes and methods the Rectangle class requires and create a class that will satisfy the requirements.

• Add only one feature at a time
• You may need to comment out parts of the main function for testing
• Constructor should take 0, 1, or 2 parameters (illustrating polymorphism)
• Your class should be a subclass of something (illustrating inheritance)
• Your class should have methods and properties (illustrating encapsulation)
• Make your instance variables hidden (using the __ trick)
• Add setter and getter methods for each instance variable
• Use properties to encapsulate instance variable access
• Not all instance variables are real... Some are derived, and should be write-only
• You may not substantially change the main function (unless you're doing the blackbelt challenge)
• Be sure to add the needed code to run the main function when needed

Here is the rubric

• Code: main() function is relatively unchanged 3
• Code: Rectangle class is declared with defaults so it supports 0, 1 and 2 parameters 3
• Code: Instantiates Rectangle(5,7) 2
• Code: Instantiates Rectangle() 2
• Code: Rectangle class defines __ instance variables 2
• Code: Defines getters and setters for each instance variable 2
• Code: Rectangle class include area and perimeter methods 4
• Code: Rectangle class inherits from something, even if it's object 2
• Code: Rectangle class defines width and length properties 4
• Code: Rectangle includes derived read-only instance variables 2
• Code: Invokes main when the python file is executed as main 2
• Code: Rectangle class defines getStats() method that returns a string 4
• Execution: prints Rectangle a: 1
• Execution: prints area: 35 1
• Execution: prints perimeter: 24 1
• Execution: prints Rectangle b: 1
• Execution: prints width: 10 1
• Execution: prints height: 20 1
• Execution: prints area: 200 1
• Execution: prints perimeter: 60 1

Score 40

I am given this code to start off with:

def main():
print "Rectangle a:"
a = Rectangle(5, 7)
print "area:      %d" % a.area
print "perimeter: %d" % a.perimeter

print ""
print "Rectangle b:"
b = Rectangle()
b.width = 10
b.height = 20
print b.getStats()

I am supposed to get this output:

Rectangle a:
area:      35
perimeter: 24
Rectangle b:
width:     10
height:    20
area:      200
perimeter: 60

I have gotten this far but I can not get Rectangle B to print the width and height Can you please take a look?

class Rectangle:
    def __init__(self, width=0, height=0):
        self.width = width
        self.height = height

    def area(self):
        return self.width * self.height

    def perimeter(self):
        return 2 * self.height + 2 * self.width

    def setWidth(self, width):
        self.width = width

    def setHeight(self, height):
        self.height = height

    def getStats(self):
        return "area:      %s\nperimeter: %s" % (self.area(), self.perimeter())


def main():
    print ""
    print "Rectangle a:"
    a = Rectangle(5, 7)
    print "area:      %s" % a.area()
    print "perimeter: %s" % a.perimeter()

    print ""
    print "Rectangle b:"
    b = Rectangle()
    b.width = 10
    b.height = 20
    print b.getStats()
    print ""


main()

I am currently getting this output:

Rectangle a:
area:      35
perimeter: 24

Rectangle b:
area:      200
perimeter: 60


Process finished with exit code 0