ShapeUpgrade_UnifySameDomain not working

Hello,

I am trying to unify a TopoDS_Shape consisting of a few neighbouring faces. I read that ShapeUpgrade_UnifySameDomain can be used for this. However, it does not do anything on my step file. This is the code that I am using:

ShapeUpgrade_UnifySameDomain unifyDomains(myShape);
unifyDomains.Build();
TopoDS_Shape unifiedShape = unifyDomains.Shape();

I have attached my shape step file as .txt (shape.txt. I was not allowed to upload step files, so please change the extention to ".stp").

Am I doing something wrong?

Thanks in advance,

Martijn