System.out.println("getDDXDocument got this array:\n"+os.toString());
    public static Document getDDXDocument(String dataset,                                          String constraintExpression)            throws PPTException, BadConfigurationException, IOException, JDOMException {        ByteArrayOutputStream os = new ByteArrayOutputStream();        BesAPI.writeDDX(dataset, constraintExpression, os);        SAXBuilder sb = new SAXBuilder();        return sb.build(new ByteArrayInputStream(os.toByteArray()));    }