def login_url(self, base_url):
        return url_path_join(base_url, 'login')
Filter for DB2 duplicate key errors.
dataset/ETHPy150Open jupyterhub/jupyterhub/jupyterhub/auth.py/Authenticator.login_url--crossover with--dataset/ETHPy150Open openstack/oslo.db/oslo_db/sqlalchemy/exc_filters.py/_db2_dupe_key_error