code: func (bto *BootstrapTokenOptions) AddTokenFlag(fs *pflag.FlagSet) {
  	fs.StringVar(
  		&bto.TokenStr, TokenStr, "",
  		"The token to use for establishing bidirectional trust between nodes and control-plane nodes. The format is [a-z0-9]{6}\\.[a-z0-9]{16} - e.g. abcdef.0123456789abcdef",
  	)
  }
docs: // AddTokenFlag adds the --token flag to the given flagset