I am an experienced Cognos Planning developer new to TM1. So maybe this is welcome to enlightenment or the darkside

I am attempting to write a rule in a cube so that a picklist is defined by what is chosen in another picklist, a cascasing picklist. Unfortunately I seem to be going round in circle with errors from the editor. My rule is posted below. Any advice would be greatfully received.
Code: Select all
['Fleet Assumptions':'Business Sub Type']= S: if (DB('Fleet Dimensions', !Elist, !Version, ATTRS('Fleet Assumptions','Business Type') @='Selection1','Static:Test1:Test2'));
Where Business Sub Type is the cascaded picklist and Business Type is the "master". So I want Business Sub Type to show Test1, Test 2 if Business Type is Selection1.
For info there are two business types and 5 sub types so I dont think I need to use a dynamic table of values, or a design of this sort.
Thank you
Stuart