docs: def duplicate(self, request, *args, **kwargs):
          """Duplicate (make copy of) ``Collection`` models."""
          if not request.user.is_authenticated:
              raise exceptions.NotFound
  
          ids = self.get_ids(request.data)
          queryset = get_objects_for_user(request.user, 'view_collection', Collection.objects.filter(id__in=ids))
          actual_ids = queryset.values_list('id', flat=True)
          missing_ids = list(set(ids) - set(actual_ids))
          if missing_ids:
              raise exceptions.ParseError(
                  "Collections with the following ids not found: {}".format(', '.join(map(str, missing_ids)))
              )
  
          duplicated = queryset.duplicate(contributor=request.user)
  
          serializer = self.get_serializer(duplicated, many=True)
          return Response(serializer.data)