merge-modules accepts >1 module

modules/base.nix

@@ -0,0 +1,17 @@
+{ device } :
+{ lib, ...}:
+let inherit (lib) mkEnableOption mkOption types;
+in {
+  options = {
+    systemPackages = mkOption {
+      type = types.listOf types.package;
+    };
+    services = mkOption {
+      type = types.anything;
+    };
+    kernel = mkOption {
+      type = types.anything;
+      default = { inherit (device.kernel) config checkedConfig; };
+    };
+  };
+}