#!/usr/bin/python3.9

class Animal:                       # 常
   def run(self):                        
print ('Animal is running...')    # ø෽
class Cat(Animal):                  # 
   def run(self):    
      print (Cat is running...')        #෽
class Dog(Animal):                 #
   def Dog(self):     
      print (Dog is running...')      #෽
c = Dog()                     	# ʵ
c.run()   	               # д
ϳнΪ
Dog is running...