maas-cli reports unknown operation if you're logged in with the wrong credentials

ubuntu@lenovo-RD230-01:~$ maas-cli api maas nodes list
400 BAD REQUEST

  -Content-Encoding: gzip
         Connection: close
     Content-Length: 26
       Content-Type: text/html; charset=utf-8
               Date: Fri, 28 Sep 2012 20:00:27 GMT
             Server: Apache/2.2.22 (Ubuntu)
             Status: 400
               Vary: Authorization,Cookie,Accept-Encoding

Unknown operation: 'list'.

I had previously logged in with the maas-cli using credentials that I purged. Once I logout and login with the proper credentials I could get the list of nodes.