error:
       … while evaluating the attribute 'packages."${(pkgs).stdenv.hostPlatform.system}".default'
         at /var/lib/nixbot/worktrees/956-f605fda68195-1af1a934/flake.nix:20:7:
           19|     {
           20|       packages = eachSystem (pkgs: {
             |       ^
           21|         default = pkgs.python3.pkgs.callPackage ./default.nix { };

       … while evaluating the attribute 'legacyPackages.x86_64-darwin'
         at «git+https://github.com/NixOS/nixpkgs?ref=nixpkgs-unstable&rev=716c7a2664ca8325617b8a7fbb609273f2c4cae7&shallow=1»/lib/attrsets.nix:987:47:
          986|   */
          987|   nameValuePair = name: value: { inherit name value; };
             |                                               ^
          988|

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: Nixpkgs 26.11 has dropped support for x86_64-darwin.

       The 26.05 stable branch still supports x86_64-darwin, and will
       receive security fixes until the end of 2026. If you use channels,
       you can switch to 26.05 as follows:

           $ sudo nix-channel --add https://nixos.org/channels/nixpkgs-26.05-darwin nixpkgs
           $ sudo nix-channel --update

       If this doesn’t work, you may need to run:

           # Lack of sudo is deliberate:
           $ nix-channel --remove nixpkgs

       If you use flakes, switch your flake input:

           inputs.nixpkgs = {
             url = "github:NixOS/nixpkgs/nixpkgs-26.05-darwin";
           };

       See the release notes for more information and alternatives:

         https://nixos.org/manual/nixpkgs/unstable/release-notes#x86_64-darwin-26.11