{ description = ""; inputs = { flake-compat.url = "https://flakehub.com/f/edolstra/flake-compat/1.tar.gz"; flake-utils.url = "github:numtide/flake-utils"; nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable"; }; outputs = { self, nixpkgs, flake-utils, ... }: flake-utils.lib.eachDefaultSystem (system: let pkgs = nixpkgs.legacyPackages.${system}; in { devShells.default = pkgs.mkShell { packages = with pkgs; [ lean4 python3 ]; }; }); }