public static ExtensibleLoadManagerImpl get(LoadManager loadManager) {
        if (!(loadManager instanceof ExtensibleLoadManagerWrapper loadManagerWrapper)) {
            throw new IllegalArgumentException("The load manager should be 'ExtensibleLoadManagerWrapper'.");
        }
        return loadManagerWrapper.get();
    }
@Test(timeOut = 30 * 1000)
    public void testDeleteNamespace() throws Exception {
        String namespace = "public/test-delete-namespace";
        TopicName topicName = TopicName.get(namespace + "/test-delete-namespace-topic");
        admin.namespaces().createNamespace(namespace);
        admin.namespaces().setNamespaceReplicationClusters(namespace, Sets.newHashSet(this.conf.getClusterName()));
        assertTrue(admin.namespaces().getNamespaces("public").contains(namespace));
        admin.topics().createPartitionedTopic(topicName.toString(), 2);
        admin.lookups().lookupTopic(topicName.toString());
        NamespaceBundle bundle = getBundleAsync(pulsar1, topicName).get();
        try {
            admin.namespaces().deleteNamespaceBundle(namespace, bundle.getBundleRange());
            fail();
        } catch (Exception ex) {
            assertTrue(ex.getMessage().contains("Cannot delete non empty bundle"));
        }
        admin.namespaces().deleteNamespaceBundle(namespace, bundle.getBundleRange(), true);
        admin.lookups().lookupTopic(topicName.toString());

        admin.namespaces().deleteNamespace(namespace, true);
        assertFalse(admin.namespaces().getNamespaces("public").contains(namespace));
    }