k: int = 4,
        fetch_k: int = 20,
        lambda_mult: float = 0.5,
        **kwargs: Any,
    ) -> List[Document]:
        """Return docs selected using the maximal marginal relevance."""
        raise NotImplementedError
[docs]    @classmethod
    def from_documents(
        cls: Type[VST],
        documents: List[Document],
        embedding: Embeddings,
        **kwargs: Any,
    ) -> VST:
        """Return VectorStore initialized from documents and embeddings."""
        texts = [d.page_content for d in documents]
        metadatas = [d.metadata for d in documents]
        return cls.from_texts(texts, embedding, metadatas=metadatas, **kwargs)
[docs]    @classmethod
    async def afrom_documents(
        cls: Type[VST],
        documents: List[Document],
        embedding: Embeddings,
        **kwargs: Any,
    ) -> VST:
        """Return VectorStore initialized from documents and embeddings."""
        texts = [d.page_content for d in documents]
        metadatas = [d.metadata for d in documents]
        return await cls.afrom_texts(texts, embedding, metadatas=metadatas, **kwargs)
[docs]    @classmethod
    @abstractmethod
    def from_texts(
        cls: Type[VST],
        texts: List[str],
        embedding: Embeddings,
        metadatas: Optional[List[dict]] = None,
        **kwargs: Any,
    ) -> VST:
        """Return VectorStore initialized from texts and embeddings."""
[docs]    @classmethod
    async def afrom_texts(
        cls: Type[VST],
        texts: List[str],