Auto assignment of Inventory Org to item

We have a requirement that whenever any new item is created in a class(Class X) then it should be associated with Inventory Organization(INV Y).

I have created Rule in Manage item Rule Sets but it is not working.

Rule created by me:Primary if expression= true
secondary if expression= [item].[item basic].[item class]=='Class X'
Return Value= assignedtoOrg(INV Y)