/**
  * Deserialize the list of sheets
  *
  * @param crosstabDefinitionJSON
  * @param crosstabDefinition
  * @throws Exception
  */
 private void deserializeSheets(
     JSONObject crosstabDefinitionJSON, WorkSheetDefinition crosstabDefinition) throws Exception {
   JSONArray sheetsJSON = crosstabDefinitionJSON.getJSONArray(WorkSheetSerializationUtils.SHEETS);
   List<Sheet> workSheets = new ArrayList<Sheet>();
   for (int i = 0; i < sheetsJSON.length(); i++) {
     workSheets.add(deserializeSheet(sheetsJSON.getJSONObject(i)));
   }
   crosstabDefinition.setSheets(workSheets);
 }