'Save an OAuth1 request token.
:param token: A dict with token credentials.
:param request: An oauthlib.common.Request object.
The token dictionary will at minimum include
* ``oauth_token`` the request token string.
* ``oauth_token_secret`` the token specific secret used in signing.
* ``oauth_callback_confirmed`` the string ``true``.
Client key can be obtained from ``request.client_key``.
This method is used by
* RequestTokenEndpoint'

def save_request_token(self, token, request):

    raise self._subclass_must_implement(u'save_request_token')
