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

    d = endpoint.listen(factory)
    def registerCleanup(listeningPort):
        case.addCleanup(listeningPort.stopListening)
        return listeningPort
    d.addCallback(registerCleanup)
    return reportUnhandledErrors(case, d)

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

def listen(case, endpoint, factory):