docs: public List<List<String>> getFilteredPolicy(String sec, String ptype, int fieldIndex, String... fieldValues) {
          List<List<String>> res = new ArrayList<>();
  
          for (List<String> rule : model.get(sec).get(ptype).policy) {
              boolean matched = true;
              for (int i = 0; i < fieldValues.length; i ++) {
                  String fieldValue = fieldValues[i];
                  if (!fieldValue.equals("") && !rule.get(fieldIndex + i).equals(fieldValue)) {
                      matched = false;
                      break;
                  }
              }
  
              if (matched) {
                  res.add(rule);
              }
          }
  
          return res;
      }