docs: def qs_tobegraded(qs):
          '''
              A filtering of the given Submission queryset for all submissions that are gradeable. This includes the following cases:
  
              - The submission was submitted and there are no tests.
              - The submission was successfully validity-tested, regardless of the full test status (not existent / failed / success).
              - The grading was already started, but not finished.
  
              The idea is to get a list of work to be done for the correctors.
          '''
          return qs.filter(state__in=[Submission.SUBMITTED, Submission.SUBMITTED_TESTED, Submission.TEST_FULL_FAILED, Submission.GRADING_IN_PROGRESS])