code: func fmtDockerOpts(opts []dockerOpt, sep rune) []string {
  	fmtOpts := make([]string, len(opts))
  	for i, opt := range opts {
  		fmtOpts[i] = fmt.Sprintf("%s%c%s", opt.key, sep, opt.value)
  	}
  	return fmtOpts
  }
docs: // fmtDockerOpts formats the docker security options using the given separator.