Provide the machine-id for machine/virtualization combination

def get_machine_id():
    '''
    Provide the machine-id for machine/virtualization combination
    '''
    # Provides:
    #   machine-id
    if platform.system() == 'AIX':
        return _aix_get_machine_id()

    locations = ['/etc/machine-id', '/var/lib/dbus/machine-id']
    existing_locations = [loc for loc in locations if os.path.exists(loc)]
    if not existing_locations:
        return {}
    else:
        with salt.utils.files.fopen(existing_locations[0]) as machineid:
            return {'machine_id': machineid.read().strip()}