Comment 8 for bug 891442

There is a conflation of password and api_key in novaclient which is inappropriate. If you take a look at python-keystoneclient, I actually separated the two because there are cases (at least in keystone) where they need to be handled differently.

Positional arguments are easier for making things "required" but also get ugly for backwards compatibility across changes to the function signature. Keyword arguments are both easier to work with (you don't have to memorize the order) and more forwards-compatible. If you want t make them required, just raise a ValueError if a required keyword argument is present.