'Verify that the given OAuth1 request token is valid.
:param token: A request token string.
:param request: An oauthlib.common.Request object.
:returns: True or False
This method is used only in AuthorizationEndpoint to check whether the
oauth_token given in the authorization URL is valid or not.
This request is not signed and thus similar ``validate_request_token``
method can not be used.
This method is used by
* AuthorizationEndpoint'

def verify_request_token(self, token, request):

    raise self._subclass_must_implement(u'verify_request_token')
