anchor.diff:                pkgs.python3.pkgs.sphinx
                 pkgs.yamllint
               ];
  -        });
  +        };
  +      });
       };
   }
  
positive.code:       pythonAttrs = lib.filterAttrs (name: _: isPython name);
  
      in {
        overlay = final: prev:
          {
            bifrost = final.callPackage bifrost { };
            bifrost-doc = final.callPackage bifrost-doc { };
  
negative.code: 
          in { inherit (pkgs) bifrost-doc; } // cgens // bfs // pys);
  
        devShells = eachSystem (pkgs: {
          default = let
            pre-commit = pre-commit-hooks.lib.${pkgs.system}.run {
              src = ./.;
              hooks.nixfmt.enable = true;
  