code: func (fs *FlagSet) Parse(line string) error {
  	var args []string
  	for _, token := range lexer(line, ',').split() {
  		name, value := token.split()
  		args = append(args, fmt.Sprintf("-%s", name))
  		if value != "" {
  			args = append(args, value)
  		}
  	}
  
  	return fs.F.Parse(args)
  }
docs: // Parse parses a one-line option string into the underlying flag set.