src/transformers/models/rag/retrieval_rag.py/LegacyIndex/_load_passages
class LegacyIndex:    def _load_passages(self):
        logger.info(f"Loading passages from {self.index_path}")
        passages_path = self._resolve_path(self.index_path, self.PASSAGE_FILENAME)
        with open(passages_path, "rb") as passages_file:
            passages = pickle.load(passages_file)
        return passages