human
I wrote the below code

    if (__opts__.get('__role') == 'master'):
        fire_master = salt.utils.event.get_master_event(__opts__, __opts__['sock_dir']).fire_event
    else:
        fire_master = None
    def fire(tag, msg):
        '\n                                How    to    fire    the    event\n                                '
        if fire_master:
            fire_master(msg, tag)
        else:
            __salt__['event.send'](tag, msg)
    client = docker.Client(base_url=docker_url, timeout=timeout)
    try:
        events = client.events()
        for event in events:
            data = json.loads(event.decode(__salt_system_encoding__, errors='replace'))
            if data['Action']:
                fire('{0}/{1}'.format(tag, data['Action']), data)
            else:
                fire('{0}/{1}'.format(tag, data['status']), data)
    except Exception:
        traceback.print_exc()

What's a good function header?

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

def start(docker_url='unix://var/run/docker.sock', timeout=CLIENT_TIMEOUT, tag='salt/engines/docker_events'):