minor improvements

* added ability to override source
* use inherit (I heard that this improves performance)

balatromobile/package.nix

@@ -2,13 +2,16 @@
   fetchgit,
   python3Packages,
   jre,
-  ...
-}: let
-  src = fetchgit {
+  balatromobileSrc ?
+    fetchgit {
       url = "https://github.com/antipatico/balatromobile";
-    sha256 = "P6MVmDiI6NLHqBYdkbtqExHKjkjLeD5bE/kTEyPxVTw=";
+      hash = "sha256-P6MVmDiI6NLHqBYdkbtqExHKjkjLeD5bE/kTEyPxVTw=";
       fetchLFS = true;
-  };
+    },
+}: let
+  inherit (python3Packages) flit tabulate;
+
+  src = balatromobileSrc;
   pname = (builtins.fromTOML (builtins.readFile "${src}/pyproject.toml")).project.name;
   version = builtins.elemAt (builtins.match ".*([0-9]+\.[0-9]+\.[0-9]+).*" (builtins.readFile "${src}/balatromobile/__version__.py")) 0;
 in
@@ -16,6 +19,6 @@ in
     inherit pname version src;
 
     pyproject = true;
-    build-system = [python3Packages.flit];
-    dependencies = [python3Packages.tabulate jre];
+    build-system = [flit];
+    dependencies = [tabulate jre];
   }