New to Nix OS. Please help

I just downloaded Nix OS and I just wanted to remove some gnome app (e.g. gnome web, tour, etc.)

and i followed this guide https://discourse.nixos.org/t/howto-disable-most-gnome-default-applications-and-what-they-are/13505/5 and now I get this error

error: syntax error, unexpected '=', expecting end of file

       at /etc/nixos/configuration.nix:131:35:

          130| #
          131| environment.gnome.excludePackages = with pkgs.gnome; [
             |                                   ^
          132|     baobab      # disk usage analyzer
(use '--show-trace' to show detailed location information)
building Nix...
error: syntax error, unexpected '=', expecting end of file

       at /etc/nixos/configuration.nix:131:35:

          130| #
          131| environment.gnome.excludePackages = with pkgs.gnome; [
             |                                   ^
          132|     baobab      # disk usage analyzer
(use '--show-trace' to show detailed location information)
building the system configuration...
error: syntax error, unexpected '=', expecting end of file

       at /etc/nixos/configuration.nix:131:35:

          130| #
          131| environment.gnome.excludePackages = with pkgs.gnome; [
             |                                   ^
          132|     baobab      # disk usage analyzer
(use '--show-trace' to show detailed location information)