langchain/retrievers/weaviate_hybrid_search.py/WeaviateHybridSearchRetriever/__init__
class WeaviateHybridSearchRetriever:    def __init__(
        self,
        client: Any,
        index_name: str,
        text_key: str,
        alpha: float = 0.5,
        k: int = 4,
        attributes: Optional[List[str]] = None,
        create_schema_if_missing: bool = True,
    ):
        try:
            import weaviate
        except ImportError:
            raise ImportError(
                "Could not import weaviate python package. "
                "Please install it with `pip install weaviate-client`."
            )
        if not isinstance(client, weaviate.Client):
            raise ValueError(
                f"client should be an instance of weaviate.Client, got {type(client)}"
            )
        self._client = client
        self.k = k
        self.alpha = alpha
        self._index_name = index_name
        self._text_key = text_key
        self._query_attrs = [self._text_key]
        if attributes is not None:
            self._query_attrs.extend(attributes)

        if create_schema_if_missing:
            self._create_schema_if_missing()