code: def get_queryset(self, request):
          ''' Restrict the listed submission for the current user.'''
          qs = super(SubmissionAdmin, self).get_queryset(request)
          if request.user.is_superuser:
              return qs
          else:
              return qs.filter(Q(assignment__course__tutors__pk=request.user.pk) | Q(assignment__course__owner=request.user)).distinct(f get_queryset(self, request):
          ''' Restrict the listed submission for the current user.'''
          qs = super(SubmissionAdmin, self).get_queryset(request)
          if request.user.is_superuser:
              return qs
          else:
              return qs.filter(Q(assignment__course__tutors__pk=request.user.pk) | Q(assignment__course__owner=request.user)).distinct()
docs: Restrict the listed submission for the current user.