{
  inputs.flake-utils.url = "github:numtide/flake-utils";
  outputs = { self, flake-utils, nixpkgs }:
    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
      let
        pkgs = nixpkgs.legacyPackages.${system};
        flakePkgs = rec {
          sm2 = pkgs.python39Packages.callPackage ./sm2 {};
        };
      in rec {
        defaultPackage = packages.sm2;
        packages = flake-utils.lib.flattenTree flakePkgs;
      });
}