docs: def add_signaling_arguments(parser):
      """
      Add signaling method arguments to an argparse.ArgumentParser.
      """
      parser.add_argument('--signaling', '-s', choices=[
          'copy-and-paste', 'tcp-socket', 'unix-socket'])
      parser.add_argument('--signaling-host', default='127.0.0.1',
                          help='Signaling host (tcp-socket only)')
      parser.add_argument('--signaling-port', default=1234,
                          help='Signaling port (tcp-socket only)')
      parser.add_argument('--signaling-path', default='aiortc.socket',
                          help='Signaling socket path (unix-socket only)')