{

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    berberman = {
      url = "github:berberman/flakes";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, berberman }: {
    nixosConfigurations.my-machine = nixpkgs.lib.nixosSystem {
      # ...
      modules = [
        # ...
        { nixpkgs.overlays = [ 
            # ...
            berberman.overlays
          ]; 
        }
      ];
    };
  };
}