Correctly use mkMerge

modules/zerotier/default.nix

@@ -1,14 +1,17 @@
 { config, lib, ... }:
-lib.mkMerge [
+{
-  {
+  config = lib.mkMerge [
-    services.zerotierone = {
+    {
-      enable = true;
+      services.zerotierone = {
-      joinNetworks = [ "632ea29085af0cb4" ];
+        enable = true;
-    };
+        joinNetworks = [ "632ea29085af0cb4" ];
-  }
+      };
-  (lib.optionalAttrs (config.networking.hostName == "sisko") {
+
-    environment.persistence."/persist".directories = [
+    }
-      "/var/lib/zerotier-one"
+    (lib.mkIf (config.networking.hostName == "sisko") {
-    ];
+      environment.persistence."/persist".directories = [
-  })
+        "/var/lib/zerotier-one"
-]
+      ];
+    })
+  ];
+}