docs: def limit_author_choices():
      """ Limit choices in blog author field based on config settings """
      LIMIT_AUTHOR_CHOICES = getattr(settings, 'BLOG_LIMIT_AUTHOR_CHOICES_GROUP', None)
      if LIMIT_AUTHOR_CHOICES:
          if isinstance(LIMIT_AUTHOR_CHOICES, str):
              limit = Q(groups__name=LIMIT_AUTHOR_CHOICES)
          else:
              limit = Q()
              for s in LIMIT_AUTHOR_CHOICES:
                  limit = limit | Q(groups__name=s)
          if getattr(settings, 'BLOG_LIMIT_AUTHOR_CHOICES_ADMIN', False):
              limit = limit | Q(is_staff=True)
      else:
          limit = {'is_staff': True}
      return limit