DMR function to use in slicer

[Cognos8]

Hi,

To improve the performance i am moving date filter to Slicer. I have created one data item with Level or hierarchy reference like below, but  throws below error. Please provide your comments

intersect(lastPeriods(-9999, [gosldw_sales].[Time (ship date)].[Time (ship date)].[Day (ship date)].[Date (ship date)] ->?fromDate?),
lastPeriods(9999, [gosldw_sales].[Time (ship date)].[Time (ship date)].[Day (ship date)].[Date (ship date)] ->?ToDate?))


Error :An invalid value was assigned to Prompt 'Parameter1'. The prompt expects a member, but the value assigned is not a member.


Then i included member ref and getting below error

intersect(lastPeriods(-9999, [gosldw_sales].[Time (ship date)].[Time (ship date)].[Day (ship date)].[Date (ship date)] ->?Parameter1?),
lastPeriods(9999, [gosldw_sales].[Time (ship date)].[Time (ship date)].[Day (ship date)].[Date (ship date)] ->?Parameter2?))

Error desc:

Invalid expression '[gosldw_sales].[Time (ship date)].[Time (ship date)].[Day (ship date)].[Date (ship date)]' on left hand side of '->' for a member parameter for data item 'Data Item1', expected a level or hierarchy reference.