for result in res[0]:
            meta = result.get(self.field_metadata)
            if meta is not None:
                meta = json.loads(meta)
            doc = Document(page_content=result.get(self.field_text), metadata=meta)
            pair = (doc, result.get("score", 0.0))
            ret.append(pair)
        return ret
[docs]    def max_marginal_relevance_search(
        self,
        query: str,
        k: int = 4,
        fetch_k: int = 20,
        lambda_mult: float = 0.5,
        param: Optional[dict] = None,
        expr: Optional[str] = None,
        timeout: Optional[int] = None,
        **kwargs: Any,
    ) -> List[Document]:
        """Perform a search and return results that are reordered by MMR."""
        embedding = self.embedding_func.embed_query(query)
        return self.max_marginal_relevance_search_by_vector(
            embedding=embedding,
            k=k,
            fetch_k=fetch_k,
            lambda_mult=lambda_mult,
            param=param,
            expr=expr,
            timeout=timeout,
            **kwargs,
        )
[docs]    def max_marginal_relevance_search_by_vector(
        self,
        embedding: list[float],
        k: int = 4,
        fetch_k: int = 20,
        lambda_mult: float = 0.5,
        param: Optional[dict] = None,
        expr: Optional[str] = None,
        timeout: Optional[int] = None,
        **kwargs: Any,
    ) -> List[Document]:
        """Perform a search and return results that are reordered by MMR."""