langchain/vectorstores/tair.py/Tair/add_texts
class Tair:    def add_texts(
        self,
        texts: Iterable[str],
        metadatas: Optional[List[dict]] = None,
        **kwargs: Any,
    ) -> List[str]:
        """Add texts data to an existing index."""
        ids = []
        keys = kwargs.get("keys", None)
        # Write data to tair
        pipeline = self.client.pipeline(transaction=False)
        embeddings = self.embedding_function.embed_documents(list(texts))
        for i, text in enumerate(texts):
            # Use provided key otherwise use default key
            key = keys[i] if keys else _uuid_key()
            metadata = metadatas[i] if metadatas else {}
            pipeline.tvs_hset(
                self.index_name,
                key,
                embeddings[i],
                False,
                **{
                    self.content_key: text,
                    self.metadata_key: json.dumps(metadata),
                },
            )
            ids.append(key)
        pipeline.execute()
        return ids