Rearrange flake.nix to call mkPoetryEnv directly instead of with mkShell

flake.nix

@@ -26,32 +26,26 @@
         python = pkgs.python310;
       in
       {
-        #apps = {
-          #nancy = pkgs.nancy;
-        #};
-        #defaultApp = pkgs.nancy;
-
         defaultPackage = pkgs.nancy;
 
-
-        devShell = pkgs.mkShell {
-          buildInputs = with pkgs; with python.pkgs; [
-            nixpkgs-fmt
-            black
-            poetry
-            pkgs.pre-commit
-            sqlite
-            (pkgs.poetry2nix.mkPoetryEnv {
+        devShell =
+          let
+            e = pkgs.poetry2nix.mkPoetryEnv {
               inherit python;
               projectDir = ./.;
-              pyproject = ./pyproject.toml;
-              poetrylock = ./poetry.lock;
               editablePackageSources = {
                 nancy = ./src;
               };
-            })
-          ];
-          shellHook = "echo 'Execute `poetry shell` to access an environment with an editable install.'";
-        };
+            };
+          in
+          e.env.overrideAttrs (oldAttrs: {
+            buildInputs = with pkgs; with python.pkgs; [
+              nixpkgs-fmt
+              black
+              poetry
+              pkgs.pre-commit
+              sqlite
+            ];
+          });
       }));
 }