def close(self, cardinal):
        cardinal.event_manager.remove_callback(
            "urls.detection", self._callback_id)
Note that `cls` is either an actor or an action. And remember that
dataset/ETHPy150Open JohnMaguire/Cardinal/plugins/wikipedia/plugin.py/WikipediaPlugin.close--crossover with--dataset/ETHPy150Open lsaffre/lino/lino/core/actions.py/register_params