@Test
 public void listing3_7_create_movies() {
   try (Transaction tx = graphDb.beginTx()) {
     assertNotNull(graphDb.getNodeById(3));
     assertNotNull(graphDb.getNodeById(4));
     assertNotNull(graphDb.getNodeById(5));
     tx.success();
   }
 }
 @Test
 public void listing3_2_create_single_user() {
   usersAndMovies.createSingleUser();
   try (Transaction tx = graphDb.beginTx()) {
     assertNotNull(graphDb.getNodeById(0));
     tx.success();
   }
 }
 @Test
 public void listing3_3_create_multiple_users() {
   usersAndMovies.createMultipleUsersInSingleTransaction();
   try (Transaction tx = graphDb.beginTx()) {
     assertNotNull(graphDb.getNodeById(1));
     assertNotNull(graphDb.getNodeById(2));
     tx.success();
   }
 }