code: public Object value(int i, String key) {
          Object data = getData();
          if (data instanceof List) {
              List list = (List) data;
              if (list.size() > 0) {
                  Map map = (Map) list.get(i);
                  return map.get(key);
              }
          } else if (data instanceof Map) {
              return ((Map) data).get(key);
          }
          return null;
      }
docs: read the value of the specified index and key in this response object.
  
  @param i   the index
  @param key the key
  @return the value