code: def qmnist():
      return itertools.chain.from_iterable(
          [
              collect_urls(
                  datasets.QMNIST, ROOT, what=what, download=True
              )
              for what in ("train", "test", "nist")
          ]
      )
  
imports: import contextlib
  import itertools
  import tempfile
  import time
  import traceback
  import unittest.mock
  import warnings
  from datetime import datetime
  from distutils import dir_util
  from os import path
  from urllib.error import HTTPError, URLError
  from urllib.parse import urlparse
  from urllib.request import Request, urlopen
  import pytest
  from torchvision import datasets
  from torchvision.datasets.utils import _get_redirect_url, USER_AGENT
label_desc: Use image node_id 19 for calling a global function with example usage: qmnist() and returns: itertools