>>> import monai
>>> url = "https://github.com/Project-MONAI/MONAI-extra-test-data/releases/download/0.8.1/MedNIST.tar.gz"

>>> monai.apps.utils.download_and_extract(url, filepath=".")
2022-11-03 15:15:04,858 - INFO - Expected md5 is None, skip md5 check for file ..
2022-11-03 15:15:04,858 - INFO - File exists: ., skipped downloading.
2022-11-03 15:15:04,858 - INFO - Non-empty folder exists in ., skipped extracting.

>>> monai.apps.utils.download_and_extract(url, filepath="./test")
test: 59.0MB [00:09, 6.22MB/s]                                                                                                                                                                                     
2022-11-03 15:16:23,355 - INFO - Downloaded: test
2022-11-03 15:16:23,356 - INFO - Expected md5 is None, skip md5 check for file test.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/Documents/MONAI/monai/apps/utils.py", line 313, in download_and_extract
    extractall(filepath=filename, output_dir=output_dir, file_type=file_type, has_base=has_base)
  File "/Users/Documents/MONAI/monai/apps/utils.py", line 256, in extractall
    if cache_dir.exists() and next(cache_dir.iterdir(), None) is not None:
  File "/usr/local/anaconda3/envs/py38/lib/python3.8/pathlib.py", line 1122, in iterdir
    for name in self._accessor.listdir(self):
NotADirectoryError: [Errno 20] Not a directory: 'test'