{ inputs, ... }:
{

  nixpkgs-unstable = final: _prev: {
    unstable = import inputs.nixpkgs-unstable {
      system = final.system;
      config.allowUnfree = true;
    };
  };

  nixpkgs-stable = final: _prev: {
    stable = import inputs.nixpkgs-stable {
      system = final.system;
      config.allowUnfree = true;
    };
  };
}