How to pass additional arguments by launching flux via command line?

I'm looking for an option to pass additional arguments by launching flux via command line? (Doc link: here)
In python (e.g. with PyCharm) you can pass extra parameters in the "run configurations" and access them with "sys.argv".
I tried to add my own environment variable in the command line, but can't find it / get access in the flux project.

Example 1:

"C:\Altair\2019\flux\Flux\Bin\prg\win64\flux.exe" –application Flux2D –file C:\work\Project_2D.FLU -env MYVAR="asddg"

Here I cant find MYVAR.

Example 2:

"C:\Altair\2019\flux\Flux\Bin\prg\win64\flux.exe" –application Flux2D –file C:\work\Project_2D.FLU "basdsdf"

Here I get an error bc of the unknown argument in the end.

I'm using "subprocess.run()" with "shell=True" to launch the python script (which is almost equal to "os.system()")