anchor.diff:        installation instructions: https://brew.sh
       '';
   
  +    noAutoUpdate = mkOption {
  +      type = types.bool;
  +      default = true;
  +      example = false;
  +      description = ''
  +        Sets the <literal>HOMEBREW_NO_AUTO_UPDATE</literal> environment variable when running the
  +        <command>brew bundle</command> command. The default is <literal>true</literal> so that
  +        repeated invocations of <command>darwin-rebuild switch</command> are idempotent.
  +      '';
  +    };
  +
       cleanupType = mkOption {
  -      type = with types; enum [ "none" "uninstall" "zap" ];
  +      type = types.enum [ "none" "uninstall" "zap" ];
         default = "none";
         example = "uninstall";
         description = ''
  
positive.code:     system.activationScripts.brew-bundle.text = mkIf cfg.enable ''
        # Homebrew Bundle
        echo >&2 "Homebrew bundle..."
        PATH=/usr/local/bin:$PATH brew update > /dev/null
        PATH=/usr/local/bin:$PATH brew bundle ${brew-bunble-options}
      '';
    };
  
  
negative.code:     (if cfg.extraConfig != "" then "# Extra config\n" + cfg.extraConfig else "")
    );
  
    brew-bundle-command =
      "HOMEBREW_NO_AUTO_UPDATE=" +
      (if cfg.noAutoUpdate then "1" else "0") +
      " brew bundle --file='${brewfile}' --no-lock" +
      (if cfg.cleanupType == "uninstall" || cfg.cleanupType == "zap" then " --cleanup" else "") +
      (if cfg.cleanupType == "zap" then " --zap" else "");
  
  