def METHOD_NAME():
    """The main function. Hier spielt die Musik.
    """
    # parse the command line, exit with UNKNOWN if it fails
    try:
        args = parse_args()
    except SystemExit:
        sys.exit(STATE_UNKNOWN)
    head = textwrap.dedent('''
        {HOST_STATE:.4}: {HOST_DISPLAYNAME} ({DATETIME})
    ''').strip().format(
        HOST_STATE=args.HOST_STATE,
        HOST_DISPLAYNAME=args.HOST_DISPLAYNAME,
        DATETIME=args.DATETIME,
    )
    if args.NOTIFICATION_COMMENT:
        head += '\nCOMMENT: {NOTIFICATION_COMMENT} ({NOTIFICATION_AUTHOR})'.format(
            NOTIFICATION_AUTHOR=args.NOTIFICATION_AUTHOR,
            NOTIFICATION_COMMENT=args.NOTIFICATION_COMMENT,
        )
    link = None
    if args.ICINGAWEB2_URL and args.HOSTNAME:
        params = urllib.parse.urlencode(
            {
                'name': args.HOSTNAME,
            },
            quote_via=urllib.parse.quote
        )
        link = urllib.parse.urljoin(
            '{}/'.format(args.ICINGAWEB2_URL),
            'icingadb/host?{}'.format(params)
        )
    body = args.HOST_OUTPUT
    url = args.URL + '?format=full'
    headers = {
        'Content-Type': 'application/json',
        'Authorization': args.TOKEN,
    }
    data = {
        "head": {
            "text": head,
        },
        "body": [{
            "type": "message",
            "text": body,
            "link": link
        }]
    }
    result = lib.base.coe(lib.url.fetch(url,
        header=headers,
        data=data,
        encoding='serialized-json',
        extended=True,
    ))
    if result['status_code'] != 200 or result['response'] != 'OK':
        sys.exit(STATE_UNKNOWN)