code: def create_translation(self, language_code, **fields):
          
          if language_code is None:
              raise ValueError(get_null_language_error())
  
          meta = self._parler_meta
          if self._translations_cache[meta.root_model].get(language_code, None):  # MISSING evaluates to False too
              raise ValueError("Translation already exists: {0}".format(language_code))
  
          # Save all fields in the proper translated model.
          for translation in self._set_translated_fields(language_code, **fields):
              self.save_translation(translation)
docs: Add a translation to the model.
  
          The :func:`save_translations` function is called afterwards.
  
          The object will be saved immediately, similar to
          calling :func:`~django.db.models.manager.Manager.create`
          or :func:`~django.db.models.fields.related.RelatedManager.create` on related fields.