VSCode extensions setup

hm, so I am currently trying to install vscode with some extensions like so

environment.systemPackages = with pkgs; [
    (vscode-with-extensions.override {
      vscodeExtensions = with vscode-extensions; [
        "vscodevim.vim"
        "ms-dotnettools.csharp"
      ];
    })
]

but still getting this error: