'Deletes the DNS TXT record which would have been created by `_perform_achall`.
Fails gracefully if no such record exists.
:param str domain: The domain being validated.
:param str validation_domain_name: The validation record domain name.
:param str validation: The validation record content.'

@abc.abstractmethod
def _cleanup(self, domain, validation_domain_name, validation):

    raise NotImplementedError()
