code: func flagLogLevel(fs *flag.FlagSet, addr *logLevelArg, def string) {
  	if def != "" {
  		addr.Set(def)
  	}
  	fs.VarP(
  		addr,
  		"log-level",
  		"l",
  		`Sets the log level`)
  }
docs: // flagLogLevel adds the -l,--log-level flag to the specified flagset.