private List<Element> getServiceElements(Element servicesRoot) {
        if (servicesRoot.getTagName().equals("services"))
            return XML.getChildren(servicesRoot);
        List<Element> singleServiceList = new ArrayList<>(1);
        singleServiceList.add(servicesRoot);
        return singleServiceList;
    }
If the top level is &lt;services&gt;, it contains a list of services elements,
otherwise, the top level tag is a single service.
config-model/src/main/java/com/yahoo/config/model/ConfigModelRepo.java