python学习中遇到的问题

问题1：TypeError: Pool() takes no arguments

代码：

---

class Tortoise:
    def _init_(self,x):
        self.num = x

class Fish:
    def _init_(self,y):
        self.num = y

class Pool:
    def _init_(self,x,y):
        self.tortoise = Tortoise(x)
        self.fish = Fish(y)

    def print_num(self):
        print("水池里共有乌龟%d只，小鱼%d只"%(self.tortoise.num,self.fish.num))

pool = Pool(1,10)
pool.print_num()
 

结果报错：TypeError: Pool() takes no arguments

原因：是python初始化时__init__()，是两个下划线

正确代码：

class Tortoise:
    def __init__(self,x):
        self.num = x

class Fish:
    def __init__(self,y):
        self.num = y

class Pool:
    def __init__(self,x,y):
        self.tortoise = Tortoise(x)
        self.fish = Fish(y)

    def print_num(self):
        print("水池里共有乌龟%d只，小鱼%d只"%(self.tortoise.num,self.fish.num))

pool = Pool(1,10)
pool.print_num()