configuration.nix

  # Allow unfree packages
  nixpkgs.config.allowUnfree = true;
  # List packages installed in system profile. To search by name, run:
  # $ nix-env -qaP | grep wget
  environment.systemPackages = with pkgs; [
    wget
    vim
    firefox
    konsole
    git
    kate
    screen
    mosh
    gcc
    gnumake
    python36.withPackages( pypkgs: with pypkgs; [ pyqt5 ])
    dropbox-cli
    powertop
    vlc
    pkgconfig
  ];

gistfile1.txt

The option value `environment.systemPackages.[definition 39-entry 11]' in `/etc/nixos/configuration.nix' is not of type `package'.