from doctran import Doctran
            doctran = Doctran(
                openai_api_key=self.openai_api_key, openai_model=self.openai_api_model
            )
        except ImportError:
            raise ImportError(
                "Install doctran to use this parser. (pip install doctran)"
            )
        for d in documents:
            doctran_doc = (
                await doctran.parse(content=d.page_content).interrogate().execute()
            )
            questions_and_answers = doctran_doc.extracted_properties.get(
                "questions_and_answers"
            )
            d.metadata["questions_and_answers"] = questions_and_answers
        return documents