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

    def _info(vm_):
        dom = _get_domain(vm_)
        raw = dom.info()
        return {'cpu': raw[3], 'cputime': int(raw[4]), 'disks': get_disks(vm_), 'graphics': get_graphics(vm_), 'nics': get_nics(vm_), 'maxMem': int(raw[1]), 'mem': int(raw[2]), 'state': VIRT_STATE_NAME_MAP.get(raw[0], 'unknown')}
    info = {}
    if vm_:
        info[vm_] = _info(vm_)
    else:
        for vm_ in list_domains():
            info[vm_] = _info(vm_)
    return info

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

def vm_info(vm_=None):