code: def related_by_category(obj, count, collected_so_far, mods=[], only_from_same_site=True):
      
      related = []
      # top objects in given category
      if count > 0:
          from ella.core.models import Listing
          cat = obj.category
          listings = Listing.objects.get_queryset_wrapper(
              category=cat,
              content_types=[ContentType.objects.get_for_model(m) for m in mods]
          )
          for l in listings[0:count + len(related)]:
              t = l.publishable
              if t != obj and t not in collected_so_far and t not in related:
                  related.append(t)
                  count -= 1
  
              if count <= 0:
                  return related
      return related
docs: Returns other Publishable objects related to ``obj`` by using the same
      category principle. Returns up to ``count`` objects.