(Qlick Sense Cloud) Cumulative total by weeks&product groups

[#1]

Hello all,

I need your help, dear experts!

Following template:

I need to calculate cumulative total by weeks and product groups (code material).

I suppose it should be like using set expression:

sum({<Week = {"<=$ Week"} >} [Income-Outcome])

But it doesn't work...

Thank you in advance!

Regards,

Tima