open/close threads with `<' and `>'

[Harry Putnam]

I once had some code in .gnus that I cabbaged onto somewhere on the
internet. It allowed me to open and close threads with the right left
arrow keys.  Somewhere along the way I lost it.

Suddenly as of a week or two It hasn't worked... this went along with
major OS changes too.  Abandoning a long time OS (gentoo) and moving to
debian. 

Cutting to the chase; does anyone here happen to have code that allows
<> to open/close threads, that I can steel?  It would take a major
makeover for me to be able to write it myself.