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

    mimic_config = {'realtime': True, 'listen': '0', 'verbose': True}
    mimic_service = mimic_make_service(mimic_config)
    mimic_service.startService()
    test_case.addCleanup(mimic_service.stopService)
    [site_service] = mimic_service.services
    waiting_for_port = site_service._waitingForPort
    def stop_the_port(listening_port):
        test_case.addCleanup((lambda : listening_port.stopListening()))
        return listening_port
    listening = waiting_for_port.addCallback(stop_the_port)
    return listening

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

def mimic_for_test(test_case):