code: def pre_save(self, instance, add: bool):
          
  
          slugs = LocalizedValue()
  
          for lang_code, value in self._get_populate_values(instance):
              if not value:
                  continue
  
              if self.include_time:
                  value += '-%s' % datetime.now().microsecond
  
              def is_unique(slug: str, language: str) -> bool:
                  """Gets whether the specified slug is unique."""
  
                  unique_filter = {
                      '%s__%s' % (self.name, language): slug
                  }
  
                  return not type(instance).objects.filter(**unique_filter).exists()
  
              slug = self._make_unique_slug(
                  slugify(value, allow_unicode=True),
                  lang_code,
                  is_unique
              )
  
              slugs.set(lang_code, slug)
  
          setattr(instance, self.name, slugs)
          return slugs
docs: Ran just before the model is saved, allows us to built
          the slug.
  
          Arguments:
              instance:
                  The model that is being saved.
  
              add:
                  Indicates whether this is a new entry
                  to the database or an update.