Modules Defined in Another Module? (nix-darwin)

I am trying to use nix-darwin to setup my computers. Currently just a single osx machine which is working great. I’m trying to break my flake.nix apart into multiple files so I can start generalizing and making modules, etc for different machines. I was able to pull most of the config out except one section in the modules regarding homebrew. How do I pull the nix-homebrew and mac-app-utils into another file (say darwin.nix)?

    outputs = inputs@{ self, nix-darwin, nixpkgs, nix-homebrew, homebrew-core, homebrew-cask, homebrew-bundle, mac-app-util, ... }: {
        darwinConfigurations."ApplePi" = nix-darwin.lib.darwinSystem {
          modules = [
            ./darwin.nix
            nix-homebrew.darwinModules.nix-homebrew {
              nix-homebrew = 
                {
                  # Install Homebrew under the default prefix
                  enable = true;

                  # Apple Silicon Only: Also install Homebrew under the default Intel prefix for Rosetta 2
                  enableRosetta = true;

                  # User owning the Homebrew prefix
                  user = "me";

                  # Optional: Declarative tap management
                  taps = 
                    {
                      "homebrew/homebrew-core" = homebrew-core;
                      "homebrew/homebrew-cask" = homebrew-cask;
                      "homebrew/homebrew-bundle" = homebrew-bundle;
                    };

                  # Optional: Enable fully-declarative tap management
                  #
                  # With mutableTaps disabled, taps can no longer be added imperatively with `brew tap`.
                  mutableTaps = false;
              };
            } 

           mac-app-util.darwinModules.default
          ];
        };
    };