code: def get_indexable(cls):
          
          model = cls.get_model()
          return model.objects.order_by('id').values_list('id', flat=True)
docs: Returns the queryset of ids of all things to be indexed.
  
          Defaults to::
  
              cls.get_model().objects.order_by('id').values_list(
                  'id', flat=True)
  
          :returns: iterable of ids of objects to be indexed