class FirstClass: # define a class object
def setdata(self, value): # define class methods
self.data = value # self is the instance
def display(self):
print self.data # self.data: per instance
class SecondClass(FirstClass): # inherits setdata
def display(self): # changes display
print 'Current value = "%s"' % self.data
z = SecondClass()
z.setdata(42) # setdata found in FirstClass
z.display() # finds overridden method in SecondClass