Try to obtain token from all end-points that were ever used to serve the
        token. If the request returns 404 NOT FOUND, retry with older version of
        the URL.

def obtain_token(self):
        """
        Try to obtain token from all end-points that were ever used to serve the
        token. If the request returns 404 NOT FOUND, retry with older version of
        the URL.
        """
        token_end_points = ('token/obtain',
                            'obtain-token',
                            'obtain_token')
        for end_point in token_end_points:
            try:
                return self.auth[end_point]._(page_size=None)['token']
            except BeanBagException as e:
                if e.response.status_code != 404:
                    raise
        raise Exception('Could not obtain token from any known URL.')