langchain/vectorstores/annoy.py/Annoy/add_texts
class Annoy:    def add_texts(
        self,
        texts: Iterable[str],
        metadatas: Optional[List[dict]] = None,
        **kwargs: Any,
    ) -> List[str]:
        raise NotImplementedError(
            "Annoy does not allow to add new data once the index is build."
        )