aliased_dict.py

class AliasedDict(dict):
    def __init__(self, mapping):
        self.mapping = mapping

    def __getitem__(self, key):
        if key in self.mapping:
            key = self.mapping[key]
        return super().__getitem__(key)

    def __setitem__(self, key, value):
        if key in self.mapping:
            key = self.mapping[key]
        return super().__setitem__(key, value)

if __name__ == '__main__':
    d = AliasedDict({'a': 'b', 'c': 'd'})
    d['a'] = 1
    d['c'] = 2
    print(d)