def METHOD_NAME(self):
    case_ids = CommCareCase.objects.get_open_case_ids_in_domain_by_type(
        domain=self.domain,
        case_type=get_attendee_case_type(self.domain)
    )
    for case_id in case_ids:
        helper = CaseHelper(case_id=case_id, domain=self.domain)
        helper.close(user_id=self.webuser.user_id)