running:

gitlab project update --id=ID --default-branch=master

returns error ~function do_get accepts 4 arguments, 2 given.

Please check this line:
https://github.com/gpocentek/python-gitlab/blob/master/gitlab/cli.py#L185

Function actually accepts 4 arguments. Looks like copypaste issue.
https://github.com/gpocentek/python-gitlab/blob/master/gitlab/cli.py#L165

ps
And thank you for a nice tool! It is most helpfull.