could not open port /dev/ttyUSB0: [Errno 13] Keine Berechtigung: '/dev/ttyUSB0'
This is how it looks like inside the container when running as user smarthome.
crw-rw---- 1 root 18 188, 0 Okt 26 22:37 ttyUSB0
Even adding the user 'smarthome' to the group dialout doesn't fix the issue.