code: def tags_published():
      
      from tagging.models import Tag
      from zinnia.models.entry import Entry
      tags_entry_published = Tag.objects.usage_for_queryset(
          Entry.published.all())
      # Need to do that until the issue #44 of django-tagging is fixed
      return Tag.objects.filter(name__in=[t.name for t in tags_entry_published])
docs: Return the published tags.