Keeping track of sewed faces in BRepBuilderAPI_Sewing

Hello,

I would like to know how I can sew several faces into a shell, then keep track of the which face of the output shell corresponds to which input face. There is a previous discussion here:

https://www.opencascade.com/content/sewing-faces-keep-track-sewed-faces

And the suggested code is

TopoDS_Shape F = Sewer.ModifiedSubShape(originalShape);
const TopoDS_Shape& SewingResult = F.IsNull()? originalShape: F;

However after further inspection, I found that (at least in my case) SewingResult is not part of the output shell (Sewer.SewedShape()) after checking with TopExp_Explorer. Can anyone confirm, whether this is intentional, or if I am doing something wrong?

Many thanks,
Dan