@Override
    @NotNull
    public BTreeMutable getMutableCopy() {
        final BTreeMutable result = new BTreeMutable(this);
        result.addExpiredLoggable(rootLoggable);
        return result;
    }
@Test
    public void testPutSortDuplicates() {
        tm = new BTreeEmpty(log, createTestSplittingPolicy(), true, 1).getMutableCopy();

        List<INode> expected = new ArrayList<>();
        expected.add(kv("1", "1"));
        expected.add(kv("2", "2"));
        expected.add(kv("3", "3"));
        expected.add(kv("5", "51"));
        expected.add(kv("5", "52"));
        expected.add(kv("5", "53"));
        expected.add(kv("5", "54"));
        expected.add(kv("5", "55"));
        expected.add(kv("5", "56"));
        expected.add(kv("5", "57"));
        expected.add(kv("7", "7"));

        for (INode ln : expected) {
            getTreeMutable().put(ln);
        }

        assertMatchesIterator(tm, expected);
    }