code: def file_md5(
      fpath: Union[str, Path], chunk_size: int = 2**16
  ) -> Optional[str]:
      """Return md5 hash value for file contents.
  
      Args:
          fpath: Path to file.
          chunk_size: md5 object updated by ``chunk_size`` bytes from file.
  
      Returns:
          None if ``fpath`` does not point to a file, else returns md5 hash value as string.
  
      """
      fpath = Path(fpath)
      if not fpath.is_file():
          return None
      file_hash = md5()
      with fpath.open("rb") as f:
          for chunk in iter(lambda: f.read(chunk_size), b""):
              file_hash.update(chunk)
      return file_hash.hexdigest()
  
imports: import collections
  import gzip
  import os
  import secrets
  import shutil
  import tarfile
  import zipfile
  from hashlib import md5
  from itertools import chain
  from logging import getLogger
  from pathlib import Path
  from typing import Any, Generator, Iterable, List, Mapping, Optional, Sequence, Sized, Union, Collection
  from urllib.parse import urlencode, parse_qs, urlsplit, urlunsplit, urlparse
  import numpy
  import requests
  from tqdm import tqdm
label_desc: Use image node_id 9 for calling a global function with example usage: file_md5(fpath, chunk_size) and returns: file_hash, None