'Create request token.
:param consumer_id: the id of the consumer
:type consumer_id: string
:param requested_project_id: requested project id
:type requested_project_id: string
:param request_token_duration: duration of request token
:type request_token_duration: string
:returns: request_token_ref'

@abc.abstractmethod
def create_request_token(self, consumer_id, requested_project, request_token_duration):

    raise exception.NotImplemented()
