{...}: {
  imports = [
    {
      nix.settings.substituters = ["https://cache.nixos.org/"];
    }
    {
      nix.settings = {
        substituters = [
          "https://nix-community.cachix.org"
        ];
        trusted-public-keys = [
          "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
        ];
      };
    }
  ];
}
