langchain/vectorstores/mongodb_atlas.py/MongoDBAtlasVectorSearch/_insert_texts
class MongoDBAtlasVectorSearch:    def _insert_texts(self, texts: List[str], metadatas: List[Dict[str, Any]]) -> List:
        if not texts:
            return []
        # Embed and create the documents
        embeddings = self._embedding.embed_documents(texts)
        to_insert = [
            {self._text_key: t, self._embedding_key: embedding, **m}
            for t, m, embedding in zip(texts, metadatas, embeddings)
        ]
        # insert the documents in MongoDB Atlas
        insert_result = self._collection.insert_many(to_insert)
        return insert_result.inserted_ids