How to insert variable into subprocess?

Question

Python

arhiv = .....
result = subprocess.call(['tar', 'xvf' , '/home/ ??'])
The "arhiv" variable is equal to the name of the archive in the /home directory, which is parsed by date, it should be unzip.
I need instead - insert the "arhiv" variable, because the "arhiv" variable contains the file name, which is constantly changing
How to insert the arhiv variable into subprocess ? .format(arhiv) doesn't help, swears at str
python2.4
Thanks in advance!

Answer 1

arhiv = '/home/' + filename

result = subprocess.call(['tar', 'xvf' ,  arhiv])

Answer 2

result = subprocess.call(['tar',  'xvf' ,  '/home/ ??'])