Wiki is misleading when trying to set up just a basic flake for a dev shell

This wiki page: Flakes - NixOS Wiki

This section:

This is the flake I made that eventually works with nix develop:

    description = "Python dev shell";

    inputs = {
        nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
        #stable.url = "github:NixOS/nixpkgs/nixos-23.05";
        flake-utils.url = "github:numtide/flake-utils";

    outputs = {self, nixpkgs,  flake-utils}: 
            let pkgs = import nixpkgs { inherit system; };
            in {
                devShells.default = pkgs.mkShell {
                    buildInputs = [
                        (pkgs.python311.withPackages (p: with p; [ 
                    shellHook = "zsh";

You may note that the devShells line contains devShells.default rather than devShells.${system}.default

When I had the line with ${system} in it, I was getting errors:
nix flake check
error: flake attribute 'devShells.aarch64-darwin.aarch64-darwin' is not a derivation

nix develop
error: flake 'git+file:///███████████' does not provide attribute 'devShells.x86_64-linux.default', 'devShell.x86_64-linux', 'packages.x86_64-linux.default' or 'defaultPackage.x86_64-linux' Did you mean devShells?

Am I wrong, or is the wiki? Where should I have looked first to get a basic working example of a working flake-based dev shell?

Should I just paste my flake into the wiki as an example for others?

You’re not wrong, and neither is the wiki. You’re using flake-utils.lib.eachDefaultSystem, the wiki example isn’t.

Damn it, you’re right.