Read-write lock for Python

[Geoff Bache]

Hi all,

I currently find myself needing a Python read-write lock. I note that
there is none in the standard library, but googling "python read-write
lock" quickly produced 6 different competing examples, including two
languishing patch proposals for the standard library.

I can always pick a random one and hope for the best, but I was hoping
someone here might have a tip for one that has been used and debugged
and is likely to work.

Regards,
Geoff Bache