For example in batch (windows) you can use %CD%\ or .\ to start something from cwd but I dont know how to do it on python...
I triedsubprocess.call(['.\somedirectory\someprogram.exe'])
And subprocess.call(['\\somedirectory\someprogram.exe'])
edit:
Also the command I used in batch is: start %CD%\somedirectory\someprogram.exe
or start .\somedirectory\someprogram.exe