"Class parameter for loadPDIHierarchy() must be Project or Dataset.");
"Class parameter for loadPDIHierarchy() must be Project or Dataset, not "+arg0);
    public Object loadPDIHierarchy(final Class arg0, final int arg1) {        // CONTRACT        if (!Project.class.equals(arg0) && !Dataset.class.equals(arg0)) {            throw new IllegalArgumentException(                    "Class parameter for loadPDIHierarchy() must be Project or Dataset.");        }        return clean(containerDao.loadHierarchy(arg0, arg1));    }