@Nullable
    public String getCachedDescription(int start, int end, int index) {
      if (myCache == null || myCache.ranges.length != myCount) return null;

      FoldedGroupState range = getCachedState(start, end, index);
      if (range == null) return null;

      if (range.collapsed != null && range.collapsed.contains(start, end)) {
        return range.collapsedDescription != null ? range.collapsedDescription[index] : null;
      }

      return null;
    }
@Nullable
    public String getCachedDescription(int start, int end, int index)