docs: @UiThread
      public void notifyChildRangeRemoved(int parentPosition, int childPositionStart, int itemCount) {
          int flatParentPosition = getFlatParentPosition(parentPosition);
          ExpandableWrapper<P, C> parentWrapper = mFlatItemList.get(flatParentPosition);
          parentWrapper.setParent(mParentList.get(parentPosition));
  
          if (parentWrapper.isExpanded()) {
              for (int i = 0; i < itemCount; i++) {
                  mFlatItemList.remove(flatParentPosition + childPositionStart + 1);
              }
              notifyItemRangeRemoved(flatParentPosition + childPositionStart + 1, itemCount);
          }
      }