weakref.py 文件源码

def __init__(self, *args, **kw):
        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)