script stops when running from / but one volume is not mounted - how to check / ?

[miczac]

Hello, many thanks for this script!
This is on macOS 10.12.6, trying to back up a couple of external volumes.

$ sudo python ~/Downloads/checktimemachine.py 
*** Checking volume: 230GB-1
Getting list of files from source volume...
...found 20000      
Done
Getting list of files from Time Machine backup...
...98%-ish complete      
Done

Comparing, 100% complete      
Done
*** Checking volume: DATA-1TB-01
Getting list of files from source volume...
Error: "" does not exist on disk. Cannot continue!

I suspect it's simply because this DATA-1TB-01 disk is not mounted but, of course, has backups.
Is there a chance to scan / without unmounting all the disks?
Thanks a lot - Michael.

[miczac]

I just did unmount all disks but the script fails:

$ sudo python ./checktimemachine.py 
*** Checking volume: 230GB-1
Getting list of files from source volume...
Error: "" does not exist on disk. Cannot continue!

Current workaround is a line like this:
sudo find / -type d -maxdepth 1 ! -iname ".*" -exec python ./checktimemachine.py {} \;
This is not hassle-free but works for the time being.

Alas my python knowledge is much less than basic.