exemplo polimorfismo python

class Animal:
  def vocalize(self):
    print 'my vocalization'

class Cat(Animal):
  def vocalize(self):
    print 'meow'

class Dog(Animal):
  def vocalize(self):
    print 'woof woof'

zoo = [ Cat(), Dog(), Dog(), Cat(), Animal() ]

for animal in zoo:
  animal.vocalize()