How to setup RooFit for a 2D-fit in sub-ranges

Dear RooFitters,
I attach a simple example of a 2D fit with on a sub range in X and on a full range in Y.

I’m not able to set up RooFit in order to properly normalize the pdf.
I’ve tried a lot of things, but I can’t get it right.

Can you please tell me how to modify the script in attachment in order to properly fit the 2D function in the sub range and properly plot the X and Y projection superimposed to the data ?

Thank you very much.
Kind regards,