This method is used in DagFileProcessor.process_file - it may be easier to migrate all it's internal calls instead of the whole method.
self,
        file_path: str,
        pickle_dags: bool,
        dag_ids: list[str] | None,
        dag_directory: str,
        callback_requests: list[CallbackRequest],
    ):
        super().__init__()
        self._file_path = file_path
        self._pickle_dags = pickle_dags
        self._dag_ids = dag_ids
        self._dag_directory = dag_directory
        self._callback_requests = callback_requests
        
        self._process: multiprocessing.process.BaseProcess | None = None
        
        self._result: tuple[int, int] | None = None
        
        self._done = False
        
        self._start_time: datetime | None = None
        
        
        self._instance_id = DagFileProcessorProcess.class_creation_counter
        self._parent_channel: MultiprocessingConnection | None = None
        DagFileProcessorProcess.class_creation_counter += 1
    @property
    def file_path(self) -> str: