code: func AppendOptionWithPrefix(options []string, prefix string, v string) []string {
  	for i, opt := range options {
  		if strings.HasPrefix(opt, prefix) == true {
  			new_opt := opt + "," + v
  			options[i] = new_opt
  			return options
  		}
  	}
  	return append(options, prefix + v)
  }
docs: // Append to an option with given prefix