ToplevelList system = cdlDocument.getSystem();
SystemElement system = cdlDocument.getSystem();
    public void testExtendsChildExtension() throws Exception {        ParseContext context = new ParseContext();        CdlDocument cdlDocument = parseValidCDL(context,                CDL_DOC_EXTENDS_CHILD_EXTENSION);        //xpath tests to verify the stuff        ToplevelList system = cdlDocument.getSystem();        PropertyList component = lookupChildPropertyList(system,                "Component",                "");        PropertyList child = lookupChildPropertyList(component, "child2");        assertElementValueEquals(child, "text");    }