public String evaluatePathInJoin(PyExpression[] args, int endElement) {
    String result = null;
    for (int i = 0; i < endElement; i++) {
      Object arg = evaluate(args[i]);
      if (!(arg instanceof String)) {
        return null;
      }
      if (result == null) {
        result = (String)arg;
      }
      else {
        result = FileUtil.toSystemIndependentName(Paths.get(result, (String)arg).toFile().getPath());
      }
    }
    return result;
  }
public String evaluatePathInJoin(PyExpression[] args, int endElement)