code: def check_file(filename, checksum, sha1):
      if not os.path.exists(filename):
          raise ValueError("File not found: " + filename)
      if checksum and not check_sha1(filename, sha1):
          raise ValueError("Corrupted file: " + filename)
  
file_path: gluon-cv/scripts/datasets/imagenet.py
imports: import os
  import argparse
  import tarfile
  import pickle
  import gzip
  import subprocess
  from tqdm import tqdm
  from mxnet.gluon.utils import check_sha1
  from gluoncv.utils import download, makedirs
label_desc: Use image node_id 2 for calling a global function with example usage: check_file(filename, checksum, sha1) without return types