[Twisted-Python] Implementing OAuth in twisted.cred

[Yaroslav Fedevych]

> The strange bits start in the CredentialsChecker, since credentials are checked by someone else entirely.

I see nothing strange. A checker which delegates checking to another
entity and returns a Deferred. Which may go through a whole lot of
callbacks and stages of verification before your own callbacks even
start...

-- 
Engineer : How do I do it?
Economist : How much will it cost?
Twisted Developer: But does it block?