public Set<Integer> nodesThatShouldBeDown(ClusterState state) {
        return calculate(state).nodesThatShouldBeDown();
    }
@Test
    void maintenance_node_not_counted_as_down() {
        GroupAvailabilityCalculator calc = calcForHierarchicCluster(
                DistributionBuilder.withGroups(3).eachWithNodeCount(2), 0.99);
        assertThat(calc.nodesThatShouldBeDown(clusterState(
                "distributor:6 storage:6 .4.s:m")), equalTo(emptySet()));
    }