public void walk(Consumer<Tree<T>> consumer) {
		consumer.accept(this);
		final List<Tree<T>> children = getChildren();
		if (CollUtil.isNotEmpty(children)) {
			children.forEach((tree) -> tree.walk(consumer));
		}
	}
@Test
	public void walkTest() {
		List<String> ids = new ArrayList<>();
		final Tree<String> tree = TreeUtil.buildSingle(nodeList, "0");
		tree.walk((tr) -> ids.add(tr.getId()));

		assertEquals(7, ids.size());
	}