public @Nullable AbstractBlockWrapper getPrevIndentedSibling(final @NotNull AbstractBlockWrapper current) {
    if (myChildren.size() > 10) {
      return getPrevIndentedSiblingFast(current);
    }

    AbstractBlockWrapper candidate = null;
    for (AbstractBlockWrapper child : myChildren) {
      if (child.getStartOffset() >= current.getStartOffset()) return candidate;
      if (child.getWhiteSpace().containsLineFeeds()) candidate = child;
    }

    return candidate;
  }
public @Nullable AbstractBlockWrapper getPrevIndentedSibling(final @NotNull AbstractBlockWrapper current)