'Get the redirect URI associated with a request token.
:param token: The request token string.
:param request: An oauthlib.common.Request object.
:returns: The redirect URI associated with the request token.
It may be desirable to return a custom URI if the redirect is set to "oob".
In this case, the user will be redirected to the returned URI and at that
endpoint the verifier can be displayed.
This method is used by
* AuthorizationEndpoint'

def get_redirect_uri(self, token, request):

    raise NotImplementedError(u'Subclasses    must    implement    this    function.')
