How to I use controller widget selected users in an advanced query?

[Ravi Babu dasari]

Hi, I am trying to selected users in controller widget so that I could see the parent issues for these users who have at least one task in that story.

query:

Sprint in (openSprints(), futureSprints()) AND status not in (COMPLETED, ACCEPTED) AND issueFunction in parentsOf("assignee in (<username> ) ") ORDER BY summary ASC

So instead of using hardcoded user name in the above query or using currentUser(), how could I use the controller widget assignee dropdown selected options? Is there a function to get it here?