Set all marked submissions to "grading not finished".
            This is intended to support grading corrections on a larger scale.

def setGradingNotFinishedStateAction(self, request, queryset):
        '''
            Set all marked submissions to "grading not finished".
            This is intended to support grading corrections on a larger scale.
        '''
        for subm in queryset:
            subm.state = Submission.GRADING_IN_PROGRESS
            subm.save()