How to use the socketshark.constants.ERR_INVALID_SERVICE function in socketshark

assert client.log.pop() == {
            'event': 'subscribe',
            'subscription': 'invalid',
            'status': 'error',
            'error': c.ERR_INVALID_SUBSCRIPTION_FORMAT,
        }

        await session.on_client_event({
            'event': 'subscribe',
            'subscription': 'invalid.topic'
        })
        assert client.log.pop() == {
            'event': 'subscribe',
            'subscription': 'invalid.topic',
            'status': 'error',
            'error': c.ERR_INVALID_SERVICE,
        }

        assert not client.log

def validate(self):
        if not self.service or not self.topic:
            raise EventError(c.ERR_INVALID_SUBSCRIPTION_FORMAT)

        if self.service_config is None:
            raise EventError(c.ERR_INVALID_SERVICE)