public Document process(Document input) throws TransformerException {
        log.log(Level.FINE, () -> "Preprocessing overrides with " + environment + "." + region);
        Document ret = Xml.copyDocument(input);
        Element root = ret.getDocumentElement();
        applyOverrides(root, Context.empty());
        return ret;
    }
@Test(expected = IllegalArgumentException.class)
    public void testParsingDifferentEnvInParentAndChild() throws TransformerException {
        String in = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>" +
                    "<services xmlns:deploy=\"vespa\" xmlns:preprocess=\"?\" version=\"1.0\">" +
                    "  <admin deploy:environment=\"prod\" version=\"2.0\">" +
                    "    <adminserver deploy:environment=\"test\" hostalias=\"node1\"/>" +
                    "  </admin>" +
                    "</services>";
        Document inputDoc = Xml.getDocument(new StringReader(in));
        new OverrideProcessor(InstanceName.from("default"),
                              Environment.from("prod"),
                              RegionName.from("us-west"),
                              Cloud.defaultCloud().name(),
                              Tags.empty()).process(inputDoc);
    }