totally remove the legacy code path (stateful random Ops), and these 3
        APIs will be removed as well.
    *   `tf.keras.callbacks.experimental.BackupAndRestore` is now available as
        `tf.keras.callbacks.BackupAndRestore`. The experimental endpoint is
        deprecated and will be removed in a future release.

         */
        @Option(name = "-t", aliases = "--numOfThreads", metaVar = "numOfThreads", usage = "The number of threads")
        protected int numOfThreads = 1;

        /**
         * Whether to run in cleanup mode to remove old thumbnails.
         */
        @Option(name = "-c", aliases = "--cleanup", usage = "Clean-Up mode")
        protected boolean cleanup;

        /**
         * Default constructor for command-line options.

            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchDelete(new BulkList<>(list, call, entityCall), null);
    }

    // #pending create, modify, remove

            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchDelete(new BulkList<>(list, call, entityCall), null);
    }

    // #pending create, modify, remove

            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchDelete(new BulkList<>(list, call, entityCall), null);
    }

    // #pending create, modify, remove

            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchDelete(new BulkList<>(list, call, entityCall), null);
    }

    // #pending create, modify, remove

            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchDelete(new BulkList<>(list, call, entityCall), null);
    }

    // #pending create, modify, remove

            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchDelete(new BulkList<>(list, call, entityCall), null);
    }

    // #pending create, modify, remove

            RequestOptionCall<IndexRequestBuilder> entityCall) {
        return doBatchDelete(new BulkList<>(list, call, entityCall), null);
    }

    // #pending create, modify, remove

    unfiltered.put("three", 3);
    unfiltered.put("four", 4);
    assertEquals(ImmutableMap.of("two", 2, "three", 3, "four", 4), unfiltered);
    assertEquals(ImmutableMap.of("three", 3, "four", 4), filtered);

    unfiltered.remove("three");
    assertEquals(ImmutableMap.of("two", 2, "four", 4), unfiltered);
    assertEquals(ImmutableMap.of("four", 4), filtered);

    unfiltered.clear();
    assertEquals(ImmutableMap.of(), unfiltered);