def get_redirect_url(self, **kwargs):
        """
        Return the authorization/authentication URL signed with the request 
        token.
        """
        params = {
            'oauth_token': self.get_request_token().key,
        }
        return '%s?%s' % (self.auth_url, urllib.urlencode(params))
Return the authorization/authentication URL signed with the request 
        token.