Add python template.

templates/python/flake.nix

@@ -0,0 +1,53 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+    };
+  };
+  outputs = {
+    self,
+    flake-utils,
+    nixpkgs,
+    ...
+  }:
+    flake-utils.lib.eachDefaultSystem (system: let
+      inherit (pkgs) lib;
+      pkgs = import nixpkgs {
+        inherit system;
+        config = {
+          cudaSupport = true;
+          allowUnfree = true;
+        };
+      };
+      defaultPython = pkgs.python3;
+    in {
+      formatter = pkgs.alejandra;
+      devShells.default = pkgs.mkShell {
+        packages =
+          (with pkgs; [
+            ruff
+            pyright
+
+            uv
+            defaultPython
+          ])
+          ++ (with pkgs.python3Packages; [
+            pydantic
+            torchWithCuda
+          ]);
+        shellHook = ''
+          uv sync
+          . ./.venv/bin/activate
+        '';
+        env = {
+          UV_PYTHON_DOWNLOADS = "never";
+          UV_PYTHON = "${lib.getExe' defaultPython "python"}";
+          UV_TORCH_BACKEND = "auto";
+        };
+      };
+    });
+  nixConfig = {
+    keepOutputs = true;
+  };
+}