PermissionError when trying to minify a folder

[AvielBlumenfeld]

Hi,
I'm trying to simply minify a folder with some python files using the command:
pyminifier --destdir=/minified_project c:\Projects\my_proj

I get the following error message:

Traceback (most recent call last):
File "C:\Python36\lib\runpy.py", line 193, in _run_module_as_main
"main", mod_spec)
File "C:\Python36\lib\runpy.py", line 85, in run_code
exec(code, run_globals)
File "C:\Projects\my_proj\venv\Scripts\pyminifier.exe_main.py", line 9, in
File "c:\projects\my_proj\venv\lib\site-packages\pyminifier\pyminifier.py", line 393, in main
source = open(args[0]).read()
PermissionError: [Errno 13] Permission denied: 'c:\Projects\my_proj'

I'm with:
win10
python 3.6.5
pyminifier 2.1

I made sure no process is actually using this folder, python files are not read-only and I run cmd as admin.

By looking into the code of pyminifier.py on line 393, it seems like the arguments passed to the exe file weren't detected by parser.parse_args()