code: def preferred(self):
          
          if 'Preferred-Value' in self.data['record']:
              preferred = self.data['record']['Preferred-Value']
              type = self.data['type']
              if type == 'extlang':
                  type = 'language'
              return Subtag(preferred, type)
          return None
docs: Get the preferred subtag.
  
          :return: preferred :class:`language_tags.Subtag.Subtag` if exists, otherwise None.