如何在dict的构造函数中用额外的参数正确初始化dict的子类?

使用 similar approach to a previous question about subclassing a float class 在dict中不产生键。例如:

class Foo(dict):
    def __new__(cls, value, extra):
        return super().__new__(cls, value)

    def __init__(self, value, extra):
        dict.__init__(value)
        self.extra = extra

跑步 Foo({'a':1}, 1).keys() 返回空的dict键 dict_keys([]) .

如何在python中用额外的参数正确地将dict子类化?