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 =
-        devShell = pkgs.mkShell {
+          let
+            e = pkgs.poetry2nix.mkPoetryEnv {
+              inherit python;
+              projectDir = ./.;
+              editablePackageSources = {
+                nancy = ./src;
+              };
+            };
+          in
+          e.env.overrideAttrs (oldAttrs: {
             buildInputs = with pkgs; with python.pkgs; [
               nixpkgs-fmt
               black
               poetry
               pkgs.pre-commit
               sqlite
-            (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.'";
+          });
-        };
       }));
 }