public static int getLeftChildOrder(int nodeOrder) {
        return (nodeOrder << 1) + 1;
    }
@Test
    public void testLeftChildOrder() {
        assertEquals(1, MerkleTreeUtil.getLeftChildOrder(0));
        assertEquals(3, MerkleTreeUtil.getLeftChildOrder(1));
        assertEquals(5, MerkleTreeUtil.getLeftChildOrder(2));
        assertEquals(7, MerkleTreeUtil.getLeftChildOrder(3));
        assertEquals(11, MerkleTreeUtil.getLeftChildOrder(5));
    }