private MemoryFileSystem.Node getNode(String pathString, Stat stat, MemoryFileSystem.Node root) throws KeeperException.NoNodeException {
        validatePath(pathString);
        Path path = Path.fromString(pathString);
        MemoryFileSystem.Node parent = root.getNode(Paths.get(path.getParentPath().toString()), false);
        if (parent == null) throw new KeeperException.NoNodeException(path.toString());
        MemoryFileSystem.Node node = parent.children().get(path.getName());
        if (node == null) throw new KeeperException.NoNodeException(path.toString());
        if (stat != null) stat.setVersion(node.version());
        return node;
    }
Returns a node or throws the appropriate exception if it doesn't exist
zkfacade/src/main/java/com/yahoo/vespa/curator/mock/MockCuratorFramework.java