class DictAdditionalValueWrapper:

    def __init__(self, baseDict, specialKey, specialValue):
        self.baseDict = baseDict
self.specialKey = specialKey
self.specialValue = specialValue

def __getitem__(self, key):
    if key == self.specialKey:
        return self.specialValue
return self.baseDict[key]
How to pass in a dictionary with additional elements in python?