meta --subtitle doesn't set the subtitle

[dkuester]

I've tried to update a book with a subtitle. So in this case this is the before:

python3 tolinoclient.py --config .tolinoclientrc inventory

title : Star Trek - The Next Generation 05: Mehr als die Summe
subtitle : None

In this case I used this command:
python3 tolinoclient.py --config .tolinoclientrc meta --subtitle "Mehr als die Summe" --language "Deutsch" --isbn "9783942649841" bosh_XXXXXXXXXXXXXX

And then I grab the new inventory:
python3 tolinoclient.py --config .tolinoclientrc inventory

title : Star Trek - The Next Generation 05: Mehr als die Summe
subtitle : None

Same result as before, no subtitle set. As for the --language and the --isbn option, couldn't find any place to actually look them up so I don't know if they have been updated.

I suppose this is a bug?