python-zk/kazoo — pull request #56 by zsol (2013-02-26 15:40:26+00:00)
Title: watcher callback invalid only if None

We spent a painful couple of hours debugging this, hope nobody else will have to do it in the future :)

Our usecase: We passed a callback function that incidentally evaluated to `False` when used in a `bool` context, so it was never called.