docs: protected void decompressData(HashMap m) {
  
          for (Object key : m.keySet()) {
              if (m.get(key) instanceof ArrayList) {
                  // iterate sub array nodes
                  decompressData((ArrayList) m.get(key));
              } else if (m.get(key) instanceof HashMap) {
                  // iterate sub data nodes
                  decompressData((HashMap) m.get(key));
              } else {
                  // ignore other type nodes
              }
          }
  
      }