code: def save_pretrained(self, save_directory):
      os.makedirs(save_directory, exist_ok=True)
      if self.config.index_path is None:
          index_path = os.path.join(
              save_directory, "hf_dataset_index.faiss"
          )
          self.index.dataset.get_index(self.config.index_name).save(
              index_path
          )
          self.config.index_path = index_path
      self.config.save_pretrained(save_directory)
  
imports: import os
  from typing import List
  import faiss
  import numpy
  import torch
  from datasets import Dataset, load_dataset
  from PIL import Image
  from transformers import CLIPFeatureExtractor, CLIPModel, PretrainedConfig
  from diffusers import logging
label_desc: Use image node_id 4 for calling the Retriever obj's underlying member method code with example usage: obj.save_pretrained(save_directory) without return types