Python 3.x 我是python新手，我试着运行这个花哨的decorators代码

但是我得到了错误s=Square5 TypeError:Square不带参数，我无法理解它

init方法应该有双下划线。将方法更改为uu init__

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参考资料：

这是否回答了您的问题？

class Square:
    def _init_(self,side):
        self._side = side
    @property
    def side(self):
        return self._side
    @side.setter
    def side(self,value):
        if value >= 0:
            self._side = value
        else:
            print("error")
    @property
    def area(self):
        return self._side **2
    @classmethod
    def unit_square(cls):
        return cls(1)
s = Square(5)
print(s.side)
print(s.area)

def __init__(self, side):
    self._side = side