def __init__(self, fn):
        """
        load a yaml config of a job and save generated configs as yaml for each task.
        return: a list of files to run as specified by `run_task`.
        """
        if fn.endswith(".py"):
            # a python command.
            self.backend = "python"
            self.run_yamls = [fn]
            return

        job_config = recursive_config(fn)
        if job_config.base_dir is None:  # single file job config.
            self.run_yamls = [fn]
            return

        self.project_dir = os.path.join("projects", job_config.project_dir)
        self.run_dir = os.path.join("runs", job_config.project_dir)

        if job_config.run_task is not None:
            run_yamls = []
            for stage in job_config.run_task:
                # each stage can have multiple tasks running in parallel.
                if OmegaConf.is_list(stage):
                    stage_yamls = []
                    for task_file in stage:
                        stage_yamls.append(
                            os.path.join(self.project_dir, task_file))
                    run_yamls.append(stage_yamls)
                else:
                    run_yamls.append(os.path.join(self.project_dir, stage))
            self.run_yamls = run_yamls
        configs_to_save = self._overwrite_task(job_config)
        self._save_configs(configs_to_save)

        load a yaml config of a job and save generated configs as yaml for each task.
        return: a list of files to run as specified by `run_task`.
        
understand_icl/fairseq/examples/MMPT/locallaunch.py