code: def download_file(
      self, remote_filepath: str, local_filepath: str
  ) -> None:
      if not os.path.exists(remote_filepath):
          raise FileNotFoundError(
              f"The provided remote_path doesn't exist: {remote_filepath}"
          )
      if remote_filepath != local_filepath:
          shutil.copy(remote_filepath, local_filepath)
  
file_path: pytorch-lightning/src/lightning/data/streaming/downloader.py
imports: import os
  import shutil
  from abc import ABC
  from typing import Any, Dict, List
  from urllib import parse
  from lightning.data.streaming.client import S3Client
label_desc: Use image node_id 1 for calling the LocalDownloader obj's underlying member method code with example usage: obj.download_file(remote_filepath, local_filepath) without return types