"""Redirects the user to obtain OAuth authorization for this service.
The ``callback_uri`` may be omitted if you have previously
- registered a callback URI with the third-party service. For some
- sevices (including Twitter and Friendfeed), you must use a
- previously-registered callback URI and cannot specify a callback
- via this method.
+ registered a callback URI with the third-party service. For
+ some sevices (including Friendfeed), you must use a
+ previously-registered callback URI and cannot specify a
+ callback via this method.
This method sets a cookie called ``_oauth_request_token`` which is
subsequently used (and cleared) in `get_authenticated_user` for