langchain/vectorstores/mongodb_atlas.py/MongoDBAtlasVectorSearch/__init__
class MongoDBAtlasVectorSearch:    def __init__(
        self,
        client: MongoClient,
        namespace: str,
        embedding: Embeddings,
        *,
        index_name: str = "default",
        text_key: str = "text",
        embedding_key: str = "embedding",
    ):
        """
        Args:
            client: MongoDB client.
            namespace: MongoDB namespace to add the texts to.
            embedding: Text embedding model to use.
            text_key: MongoDB field that will contain the text for each
                document.
            embedding_key: MongoDB field that will contain the embedding for
                each document.
        """
        self._client = client
        db_name, collection_name = namespace.split(".")
        self._collection = client[db_name][collection_name]
        self._embedding = embedding
        self._index_name = index_name
        self._text_key = text_key
        self._embedding_key = embedding_key