{
  description = "A bare minimum OCaml flake";

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

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachDefaultSystem (sys:
      let pkgs = import nixpkgs { system = sys; };
          opkgs = pkgs.ocamlPackages; # pkgs.ocaml-ng.ocamlPackages_VERSION
          project = opkgs.buildDunePackage {
            pname = "my_project";
            version = "0.1.0";

            src = ./.;

            buildInputs = with opkgs; [
              base64
            ];
          };
      in {
        packages.default = project;
        devShells.default = pkgs.mkShell {
          packages = [ opkgs.utop ];
          inputsFrom = [ project ];
        };
      }
    );
}