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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def save_token(self, access_token):
 """ Stores the access token and additional data in redis. See :class:`oauth2.store.AccessTokenStore`. """

        self.write(access_token.token, access_token.__dict__)

        unique_token_key = self._unique_token_key(access_token.client_id,
                                                  access_token.grant_type,
                                                  access_token.user_id)
        self.write(unique_token_key, access_token.__dict__)

        if access_token.refresh_token is not None:
            self.write(access_token.refresh_token, access_token.__dict__)