TypeError: expected str, bytes or os.PathLike object, not NoneType

[ymsunsjtu]

when I run the pretrain.py, I got a problem like:
ps: I run the code on linux and in a conda env. It seems something wrong with pyinstaller?
BTW I want to know about the version of packages to run this code, may I?

Traceback (most recent call last):
File "pretrain.py", line 483, in
main()
File "pretrain.py", line 191, in main
download_chexpert_unzip(args.data)
File "/mnt/YimingSun/mia/semi-chest/utils/gcloud.py", line 76, in download_chexpert_unzip
dst_folder = Path(data_dir)
File "/home/ymsun/.conda/envs/pytorch14/lib/python3.6/pathlib.py", line 980, in new
self = cls._from_parts(args, init=False)
File "/home/ymsun/.conda/envs/pytorch14/lib/python3.6/pathlib.py", line 655, in _from_parts
drv, root, parts = self._parse_args(args)
File "/home/ymsun/.conda/envs/pytorch14/lib/python3.6/pathlib.py", line 639, in _parse_args
a = os.fspath(a)
TypeError: expected str, bytes or os.PathLike object, not NoneType