langchain/vectorstores/annoy.py/Annoy/similarity_search_with_score_by_index
class Annoy:    def similarity_search_with_score_by_index(
        self, docstore_index: int, k: int = 4, search_k: int = -1
    ) -> List[Tuple[Document, float]]:
        """Return docs most similar to query.

        Args:
            query: Text to look up documents similar to.
            k: Number of Documents to return. Defaults to 4.
            search_k: inspect up to search_k nodes which defaults
                to n_trees * n if not provided
        Returns:
            List of Documents most similar to the query and score for each
        """
        idxs, dists = self.index.get_nns_by_item(
            docstore_index, k, search_k=search_k, include_distances=True
        )
        return self.process_index_results(idxs, dists)