{
  description = "A very basic flake";

  inputs = { utils.url = "github:numtide/flake-utils"; };

  outputs = { self, nixpkgs, utils }:
    utils.lib.eachDefaultSystem (system:
      let
        pkgs = nixpkgs.legacyPackages.${system};
        myPkgs = rec { e0 = pkgs.callPackage ./. { }; };

      in rec {
        packages = utils.lib.flattenTree myPkgs;
        defaultPackage = packages.e0;
      });
}