docs: def list_with_post(self, request):
          """Endpoint handler."""
          if self.is_search_request():
              search = self.search()
  
              page = self.paginate_queryset(search)
              if page is None:
                  items = search
              else:
                  items = page
  
              try:
                  primary_keys = []
                  order_map_cases = []
                  for order, item in enumerate(items):
                      pk = item[self.primary_key_field]
                      primary_keys.append(pk)
                      order_map_cases.append(When(pk=pk, then=Value(order)))
  
                  queryset = self.get_queryset().filter(
                      pk__in=primary_keys
                  ).order_by(
                      Case(*order_map_cases, output_field=IntegerField()).asc()
                  )
              except KeyError:
                  raise KeyError("Combined viewset requires that your index contains a field with "
                                 "the primary key. By default this field is called 'id', but you "
                                 "can change it by setting primary_key_field.")
  
              # Pagination must be handled differently.
              serializer = self.get_serializer(queryset, many=True)
              if page is not None:
                  return self.get_paginated_response(serializer.data)
  
              return Response(serializer.data)
          else:
              queryset = self.filter_queryset(self.get_queryset())
              return self.paginate_response(queryset)