docs: public static boolean isVacantJson(final Object obj) {
          Collection values = null;
          if(obj instanceof Collection) {
              if(((Collection) obj).size() == 0) {
                  return true;
              }
              values = (Collection) obj;
          }
          if(obj instanceof Map) {
              if(((Map) obj).size() == 0) {
                  return true;
              }
              values = ((Map) obj).values();
          }
          int processedEmpty = 0;
          if(values != null) {
              for (Object value: values) {
                  if(!isVacantJson(value)) {
                      return false;
                  }
                  processedEmpty++;
              }
              if(processedEmpty == values.size()) {
                  return true;
              }
          }
          return false;
      }