human
Here's a good function header given the following:
I wrote the below code

    if (publisher is None):
        from twisted.python import log as publisher
    running = [None]
    def stopIfError(event):
        if (running and event.get('isError')):
            running.pop()
            reactor.stop()
    publisher.addObserver(stopIfError)
    case.addCleanup(publisher.removeObserver, stopIfError)

What's a good function header?
assistant
#Here's a good function header.

def stopOnError(case, reactor, publisher=None):