@abc.abstractmethod
    def validation(self, account_key, **kwargs):
        raise NotImplementedError()  # pragma: no cover
An ``Application`` running on a given node that has different port
dataset/ETHPy150Open letsencrypt/letsencrypt/acme/acme/challenges.py/KeyAuthorizationChallenge.validation--crossover with--dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/test/test_container.py/ApplicationNodeDeployerCalculateChangesTests.test_app_with_changed_ports_restarted