'Authorize request token.
:param request_token_id: the id of the request token, to be authorized
:type request_token_id: string
:param user_id: the id of the authorizing user
:type user_id: string
:param role_ids: list of role ids to authorize
:type role_ids: list
:returns: verifier'

@abc.abstractmethod
def authorize_request_token(self, request_token_id, user_id, role_ids):

    raise exception.NotImplemented()
