[FastAPI docs for OpenAPI](https://fastapi.tiangolo.com/how-to/extending-openapi/).
        """
        if not self.openapi_schema:
            self.openapi_schema = get_openapi(
                title=self.title,
                version=self.version,
                openapi_version=self.openapi_version,
                summary=self.summary,
                description=self.description,