ITSS Declaration Mandatory in AR Invoice for ITSS Products

If @object_type = '13' and @transaction_type in ( 'A','U')
BEGIN
If exists (select a.U_IT_Tick ,a.DocNum,  b.U_tax_name, b.DocDate , b.DocEntry 
from OINV a inner join  INV1 b on a.DocEntry = b.DocEntry
where b.U_tax_name = 'ITSS' and U_IT_Tick not in ('Y') and a.DocEntry=@list_of_cols_val_tab_del )
Select @error = 131-001,
    @error_message = 'Pls select ITSS Declaration Tick - Yes'
end