langchain/vectorstores/sklearn.py/SKLearnVectorStore/persist
class SKLearnVectorStore:    def persist(self) -> None:
        if self._serializer is None:
            raise SKLearnVectorStoreException(
                "You must specify a persist_path on creation to persist the "
                "collection."
            )
        data = {
            "ids": self._ids,
            "texts": self._texts,
            "metadatas": self._metadatas,
            "embeddings": self._embeddings,
        }
        self._serializer.save(data)