// "https://fahrkarten.bahn.de/mobile/st/li.post?lang=de"
public HTTPSession login(String login, String pin) throws IOException, SAXException {
HTTPSession session = new HTTPSession();
session.getMethod(startURL);
final String params = "login=" + login + "&pin=" + pin + "&button.login_p=Login";
String response = session.postMethod(loginURL, params);
InputStream inputStream = HTTPUtils.stringToStream(response);
LoginValidationHandler handler = new LoginValidationHandler();
reader.setContentHandler(handler);
reader.parse(new InputSource(inputStream));
if(!handler.isValid()) {