@Override
 public void removeAll(List<? extends Persistable> objList) {
   try {
     xclAdaptee.write(file, new ArrayList<ArrayList<String>>());
   } catch (RowsExceededException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
   } catch (BiffException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
   } catch (WriteException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
   } catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
   }
 }
  @Override
  public void addAll(List<? extends Persistable> objList) {
    ArrayList<ArrayList<String>> serializedList = new ArrayList<>();

    for (Persistable p : objList) {
      ArrayList<String> lineLs = p.serializeToStringArray();
      serializedList.add(lineLs);
    }
    try {
      xclAdaptee.write(file, serializedList);
    } catch (RowsExceededException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (BiffException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (WriteException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }