code: def url_to_filename(url, etag=None):
      """
      Convert `url` into a hashed filename in a repeatable way.
      If `etag` is specified, append its hash to the URL's, delimited
      by a period.
      """
      url_bytes = url.encode("utf-8")
      url_hash = sha256(url_bytes)
      filename = url_hash.hexdigest()
  
      if etag:
          etag_bytes = etag.encode("utf-8")
          etag_hash = sha256(etag_bytes)
          filename += "." + etag_hash.hexdigest()
  
      return filename
  
imports: import fnmatch
  import json
  import logging
  import os
  import shutil
  import tarfile
  import tempfile
  from functools import partial, wraps
  from hashlib import sha256
  from io import open
label_desc: Use image node_id 2 for calling a global function with example usage: url_to_filename(url, etag) and returns: filename