#!/usr/bin/python

class Class1:
  def __init__(self, data=0):
    self.data = data

  def display(self):
    print self.data

class Class2(Class1):
  def square(self):
    self.data = self.data * self.data

a = Class2(5)
a.square()       # member function specific to Class2
a.display()      # inherited member function from Class1