except ImportError:
            raise ImportError(
                "google.cloud.discoveryengine is not installed."
                "Please install it with pip install google-cloud-discoveryengine"
            )
        super().__init__(**data)
        self._client = SearchServiceClient(credentials=self.credentials)
        self._serving_config = self._client.serving_config_path(
            project=self.project_id,
            location=self.location_id,
            data_store=self.search_engine_id,
            serving_config=self.serving_config_id,
        )
    def _convert_unstructured_search_response(
        self, results: Sequence[SearchResult]
    ) -> List[Document]:
        """Converts a sequence of search results to a list of LangChain documents."""
        from google.protobuf.json_format import MessageToDict
        documents: List[Document] = []
        for result in results:
            document_dict = MessageToDict(
                result.document._pb, preserving_proto_field_name=True
            )
            derived_struct_data = document_dict.get("derived_struct_data")
            if not derived_struct_data:
                continue
            doc_metadata = document_dict.get("struct_data", {})
            doc_metadata["id"] = document_dict["id"]
            chunk_type = (
                "extractive_answers"
                if self.get_extractive_answers
                else "extractive_segments"
            )
            if chunk_type not in derived_struct_data:
                continue
            for chunk in derived_struct_data[chunk_type]:
                doc_metadata["source"] = derived_struct_data.get("link", "")
                if chunk_type == "extractive_answers":
                    doc_metadata["source"] += f":{chunk.get('pageNumber', '')}"
                documents.append(
                    Document(
                        page_content=chunk.get("content", ""), metadata=doc_metadata
                    )
                )