Defining unscheduled todos as stuck projects in Emacs Org-Mode

Question

I'm trying to setup the org-stuck-projects variable so that the "stuck projects" agenda will list all headlines which are TODOs (any TODO keyword except DONE) but those which don't have SCHEDULED or DEADLINE attributes set. Currently I get an empty list with this setting for the variable:

(setq org-stuck-projects
  '("TODO" nil nil "SCHEDULED:|DEADLINE:"))

I've checked to have some TODO'ed tasks with no scheduled date or deadline.

Answer 1

Found a solution:

'("TODO={.+}/-DONE" nil nil "SCHEDULED:\\|DEADLINE:"))

(thanks to user Jonathan Leech-Pepin for suggesting re-posting this as an answer instead of comment to the original post).