docs: public boolean removeItem(T object) {
          int size = 0;
          for (int i = 0, listsSize = lists.size(); i < listsSize; i++) {
              List<? extends T> list = lists.get(i);
              if (!(list instanceof ObservableList)) {
                  Object item = list.get(0);
                  if ((object == null) ? (item == null) : object.equals(item)) {
                      lists.remove(i);
                      modCount += 1;
                      listeners.notifyRemoved(this, size, 1);
                      return true;
                  }
              }
              size += list.size();
          }
          return false;
      }