maas-region-admin apikey command missing --username

The docs for 1.7 [1] state that to get your API Key via the command line you should run:

sudo maas-region-admin apikey my-username

Running this command you get a CommandError that you must provide a username with --username:

sudo maas-region-admin apikey admin
CommandError: You must provide a username with --username.

apt-cache policy maas-region-controller
maas-region-controller:
  Installed: 1.7.6+bzr3376-0ubuntu2~14.04.1
  Candidate: 1.7.6+bzr3376-0ubuntu2~14.04.1

[1] https://maas.ubuntu.com/docs1.7/maascli.html#api-key