class Parent:        # define parent class
   parentAttr = 100
   def __init__(self):
      print "Calling parent constructor"
 
   def parentMethod(self):
      print 'Calling parent method'
 
   def setAttr(self, attr):
      Parent.parentAttr = attr
 
   def getAttr(self):
      print "Parent attribute :", Parent.parentAttr
 
class Child(Parent): # define child class
   def __init__(self):
      print "Calling child constructor"
 
   def childMethod(self):
      print 'Calling child method'
 
c = Child()          # instance of child
c.childMethod()      # child calls its method
c.parentMethod()     # calls parent's method
c.setAttr(200)       # again call parent's method
c.getAttr()          # again call parent's method