weakref.py 文件源码

def __init__(*args, **kw):
        if not args:
            raise TypeError("descriptor '__init__' of 'WeakValueDictionary' "
                            "object needs an argument")
        self = args[0]
        args = args[1:]
        if len(args) > 1:
            raise TypeError('expected at most 1 arguments, got %d' % len(args))
        def remove(wr, selfref=ref(self)):
            self = selfref()
            if self is not None:
                if self._iterating:
                    self._pending_removals.append(wr.key)
                else:
                    del self.data[wr.key]
        self._remove = remove
        # A list of keys to be removed
        self._pending_removals = []
        self._iterating = set()
        UserDict.UserDict.__init__(self, *args, **kw)