Append an item to an OrderedDict

I needed a way to append an item to an OrderedDict, without creating a new object (too consuming) and I stumbled upon this answer on StackOverflow.

The answer gives a solution to the inverse problem (that is, prepending an item), but was good enough to be modified for my┬ásituation, without me needing to delve too much into the details of the OrderedDict data structure (it’s basically a linked list, under the hood).

Enough said, here it is for future reference:

class MyOrderedDict(OrderedDict):
    def append(self, key, value):

    root = self._OrderedDict__root
    last = root[0]

    if key in self:
        raise KeyError
    else:
        root[0] = last[1] = self._OrderedDict__map[key] = [last, root, key]
        dict.__setitem__(self, key, value)