Return a macaroon deserialized from a string
        @param serialized_json The string to decode {str}
        @return {Macaroon}

def deserialize_json(cls, serialized_json):
        '''Return a macaroon deserialized from a string
        @param serialized_json The string to decode {str}
        @return {Macaroon}
        '''
        serialized = json.loads(serialized_json)
        return Macaroon.from_dict(serialized)