except ImportError:
            raise ValueError(
                "Could not import tair python package. "
                "Please install it with `pip install tair`."
            )
        url = get_from_dict_or_env(kwargs, "tair_url", "TAIR_URL")
        try:
            if "tair_url" in kwargs:
                kwargs.pop("tair_url")
            client = TairClient.from_url(url=url, **kwargs)
        except ValueError as e:
            raise ValueError(f"Tair connection error: {e}")
        # delete index
        ret = client.tvs_del_index(index_name)
        if ret == 0:
            # index not exist
            logger.info("Index does not exist")
            return False
        return True
[docs]    @classmethod
    def from_existing_index(
        cls,
        embedding: Embeddings,
        index_name: str = "langchain",
        content_key: str = "content",
        metadata_key: str = "metadata",
        **kwargs: Any,
    ) -> Tair:
        """Connect to an existing Tair index."""
        url = get_from_dict_or_env(kwargs, "tair_url", "TAIR_URL")
        search_params = {}
        if "search_params" in kwargs:
            search_params = kwargs.pop("search_params")
        return cls(
            embedding,
            url,
            index_name,
            content_key=content_key,
            metadata_key=metadata_key,
            search_params=search_params,
            **kwargs,
        )