The argument to the `Client.__init__` method indeed is called `auth` (and expects `stormpath.auth.Auth` instance), but this instance has a `signer` member that actually returns the object that adds authentication mechanism (headers, signing, whatever's needed) to the request. The method is called that way because (in the default case) it returns `Sauthc1Signer` instance (and that naming was preserved from old SDK).

I consider both the `Auth.signer` method and `Sauthc1Signer` to be private API and fair game for renaming without considering that a compatibility break, so we can change that if needed.

But I also just noticed we already support selecting the auth method by passing `method='basic'` (instead of the default, `method='digest'`) as one of the `**auth_kwargs`.

So, this works already:

    client = Client(method='basic')

This is entirely nonobvious (such is the effect of passing `kwargs` around). So we're in a position to either document that better, or change the interface to something beter.

Thoughts? /cc @rdegges