make flake use custom amaranth

flake.nix

@@ -10,8 +10,11 @@
   };
 
   outputs =
-    inputs@{ flake-parts, ... }:
+    inputs@{ self, flake-parts, ... }:
     flake-parts.lib.mkFlake { inherit inputs; } {
+	  flake = {
+	    overlays.default = import ./python.nix;
+	  };
 
       systems = [
         "x86_64-linux"
@@ -27,7 +30,7 @@
           inputs',
           pkgs,
           system,
-          ...
+		  ...
         }:
         let
           toolchain-pkgs = with pkgs; [
@@ -38,6 +41,11 @@
           ];
         in
         {
+		  _module.args.pkgs = import inputs.nixpkgs {
+            inherit system;
+            overlays = [self.overlays.default];
+            config.allowUnfree = true;
+          };
           formatter = pkgs.nixfmt-rfc-style;
           packages.default = pkgs.python3.pkgs.buildPythonPackage {
             name = "groovylight";
@@ -53,6 +61,7 @@
             ];
 
             doCheck = true;
+        	dontCheckRuntimeDeps = 1; # nightly amaranth doesn't pass
             nativeCheckInputs =
               with pkgs;
               [