bzr - how to switch to Emacs 23 branch?

[David Reitter]

It would be great if http://www.emacswiki.org/emacs/BzrForEmacsDevs could 
explain how one gets to another branch - I have something that I believe to be 
a Bzr repository, with the "trunk" inside it, which I created according to that 
page.  

But how do I also create emacs/emacs-23 from that?  The data is surely there, 
but "bzr branches" only lists "trunk" (after several seconds wait).  I surely 
won't have to pull the branch from scratch from the server (presumably a very 
long operation)...?

So, I'd like equivalent to "git branch" (to list the branches) and "git 
checkout emacs-23".
(Sorry, this seems to be really a beginner's question, and I feel duly stupid, 
but I checked the above docs and also Canonical's "Bazaar for git users" 
page...)

Thanks
- David