Python：类的继承关系

import random as r
class Fish:
def __init__(self):
self.x=r.randint(0,10)
self.y=r.randint(0,10)
def move(self):
self.x-=1
print('我的位置是：',self.x,self.y)

class Goldfish(Fish):
pass
class Carp(Fish):
pass
class Salmon(Fish):
pass
class Shark(Fish):
def __init__(self):
self.hungry=True
    def eat(self):
if self.hungry:
print("吃货的梦想就是天天有的吃…………")
self.hungry=False
        else:
print("太累了，吃不下了")

fish=Fish()
print(fish.move())
print(fish.move())

goldfish=Goldfish()
print(goldfish.move())
print(goldfish.move())