小编yan*_*u90的帖子

这是从Learning Python第4版中提取的.它的功能是使用list子类设置.但我不明白第5行list.__init__([]),请帮忙.即使我注释掉这行代码,代码也能正常工作.为什么？

### file: setsubclass.py

class Set(list):
    def __init__(self, value = []):      # Constructor
        list.__init__([])                # Customizes list 
        self.concat(value)               # Copies mutable defaults

    def intersect(self, other):          # other is any sequence
        res = []                         # self is the subject
        for x in self:
            if x in other:               # Pick common items
                res.append(x)
        return Set(res)                  # Return a new Set

    def union(self, other):              # other is any sequence
        res = Set(self)                  # Copy me and my list
        res.concat(other)
        return …