How to implement an ordered, default dict? [duplicate]

Answer 1

Inspired by other answers on this thread, you can use something like,

from collections import OrderedDict

class OrderedDefaultDict(OrderedDict):
    def __missing__(self, key):
        value = OrderedDefaultDict()
        self[key] = value
        return value

I would like to know if there're any downsides of initializing another object of the same class in the missing method.