public ModelElement childByPath(String path) {
        StringTokenizer tokenizer = new StringTokenizer(path, ".");
        ModelElement curElem = this;
        while (tokenizer.hasMoreTokens() && curElem != null) {
            String pathElem = tokenizer.nextToken();
            ModelElement child = curElem.child(pathElem);
            if (!tokenizer.hasMoreTokens()) {
                if (child != null)
                    return child;
            }
            curElem = child;
        }
        return null;
    }
If not found, return empty list.
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/ModelElement.java