class Dog(object):
  def work(self):
    print('指哪打哪')

class ArmyDog(Dog):
  def work(self):
    print('追击敌人')
class DrugDog(Dog):
  def work(self):
    print('追查毒品')

class Person(object):
  def work_with_dog(self, dog):
    dog.work()
ad = ArmyDog()
dd = DrugDog()
daqiu = Person()
daqiu.work_with_dog(ad)
daqiu.work_with_dog(dd)

class Dog(object):
  tooth = 10
wangcai = Dog()
xiaohei = Dog()
print(Dog.tooth)
print(wangcai.tooth)
print(xiaohei.tooth)