embedding (Embedding): Embedding provider for semantic encoding and search.
            score_threshold (float, 0.2):
        Example:
        .. code-block:: python
            import langchain
            from langchain.cache import RedisSemanticCache
            from langchain.embeddings import OpenAIEmbeddings
            langchain.llm_cache = RedisSemanticCache(
                redis_url="redis://localhost:6379",
                embedding=OpenAIEmbeddings()
            )
        """
        self._cache_dict: Dict[str, RedisVectorstore] = {}
        self.redis_url = redis_url
        self.embedding = embedding
        self.score_threshold = score_threshold
    def _index_name(self, llm_string: str) -> str:
        hashed_index = _hash(llm_string)
        return f"cache:{hashed_index}"
    def _get_llm_cache(self, llm_string: str) -> RedisVectorstore:
        index_name = self._index_name(llm_string)
        # return vectorstore client for the specific llm string
        if index_name in self._cache_dict:
            return self._cache_dict[index_name]
        # create new vectorstore client for the specific llm string
        try:
            self._cache_dict[index_name] = RedisVectorstore.from_existing_index(
                embedding=self.embedding,
                index_name=index_name,
                redis_url=self.redis_url,
            )
        except ValueError:
            redis = RedisVectorstore(
                embedding_function=self.embedding.embed_query,
                index_name=index_name,
                redis_url=self.redis_url,
            )
            _embedding = self.embedding.embed_query(text="test")
            redis._create_index(dim=len(_embedding))
            self._cache_dict[index_name] = redis
        return self._cache_dict[index_name]