code: def download_and_verify(
      url, sha256=None, cache_dir=None, verbose=True, filename=None
  ):
      """Download a file to a cache directory and verify it with a sha256
      hash.
  
      Args:
          url: The file to download
          sha256: The sha256 hash to check. If the file already exists and the hash
              matches, we don't download it again.
          cache_dir: The directory in which to cache the file. The default is
              `~/.keras-ocr`.
          verbose: Whether to log progress
          filename: The filename to use for the file. By default, the filename is
              derived from the URL.
      """
      if cache_dir is None:
          cache_dir = get_default_cache_dir()
      if filename is None:
          filename = os.path.basename(urllib.parse.urlparse(url).path)
      filepath = os.path.join(cache_dir, filename)
      os.makedirs(os.path.split(filepath)[0], exist_ok=True)
      if verbose:
          print("Looking for " + filepath)
      if not os.path.isfile(filepath) or (
          sha256 and sha256sum(filepath) != sha256
      ):
          if verbose:
              print("Downloading " + filepath)
          urllib.request.urlretrieve(url, filepath)
      assert sha256 is None or sha256 == sha256sum(
          filepath
      ), "Error occurred verifying sha256."
      return filepath
  
imports: import os
  import io
  import typing
  import hashlib
  import urllib.request
  import urllib.parse
  import cv2
  import imgaug
  import numpy
  import validators
  import typing_extensions
  import matplotlib.pyplot
  from shapely import geometry
  from scipy import spatial
label_desc: Use image node_id 16 for calling a global function with example usage: download_and_verify(url, sha256, cache_dir, verbose, filename) and returns: filepath