) -> List[Document]:
        """Return docs selected using the maximal marginal relevance.
        Maximal marginal relevance optimizes for similarity to query AND diversity
        among selected documents.
        Args:
            embedding: Embedding to look up documents similar to.
            k: Number of Documents to return. Defaults to 4.
            fetch_k: Number of Documents to fetch to pass to MMR algorithm.
            lambda_mult: Number between 0 and 1 that determines the degree
                        of diversity among the results with 0 corresponding
                        to maximum diversity and 1 to minimum diversity.
                        Defaults to 0.5.
        Returns:
            List of Documents selected by maximal marginal relevance.
        """
        result = self.similarity_search_by_vector_returning_embeddings(
            embedding, fetch_k
        )
        matched_documents = [doc_tuple[0] for doc_tuple in result]
        matched_embeddings = [doc_tuple[2] for doc_tuple in result]
        mmr_selected = maximal_marginal_relevance(
            np.array([embedding], dtype=np.float32),
            matched_embeddings,
            k=k,
            lambda_mult=lambda_mult,
        )
        filtered_documents = [matched_documents[i] for i in mmr_selected]
        return filtered_documents
[docs]    def max_marginal_relevance_search(
        self,
        query: str,
        k: int = 4,
        fetch_k: int = 20,
        lambda_mult: float = 0.5,
        **kwargs: Any,
    ) -> List[Document]:
        """Return docs selected using the maximal marginal relevance.
        Maximal marginal relevance optimizes for similarity to query AND diversity
        among selected documents.
        Args:
            query: Text to look up documents similar to.