如何使用元组访问深度嵌套的字典？

这似乎有效

def __setitem__(self, key, value):    if isinstance(key, tuple):        node = self        for i in key[:-1]: try:     node = dict.__getitem__(node, i) except KeyError:     node = node[i] = type(self)()        return dict.__setitem__(node, i, value)    return dict.__setitem__(self, key, value)