this derivation will be built:
  /nix/store/s5ykqhymqrq2hhahckh9w87qh1b8rvbj-treefmt-check.drv
building '/nix/store/s5ykqhymqrq2hhahckh9w87qh1b8rvbj-treefmt-check.drv' on 'ssh-ng://customer@mac02'
building '/nix/store/s5ykqhymqrq2hhahckh9w87qh1b8rvbj-treefmt-check.drv'
treefmt-check> treefmt v2.5.0traversed 99 files
treefmt-check> emitted 91 files for processing
treefmt-check> formatted 91 files (1 changed) in 2.713s
treefmt-check>  M nixosModules/master.nix
treefmt-check> diff --git a/nixosModules/master.nix b/nixosModules/master.nix
treefmt-check> index 983beb2..5d72f7d 100644
treefmt-check> --- a/nixosModules/master.nix
treefmt-check> +++ b/nixosModules/master.nix
treefmt-check> @@ -34,12 +34,14 @@ let
treefmt-check>        ]
treefmt-check>        name;
treefmt-check>  
treefmt-check> -  getAttrTag = attr:
treefmt-check> +  getAttrTag =
treefmt-check> +    attr:
treefmt-check>      let
treefmt-check>        names = lib.attrNames attr;
treefmt-check>      in
treefmt-check> -      assert lib.assertMsg (lib.length names == 1) "attribute set doesn't contain just one attribute, instead it contains: ${lib.concatStringsSep ", " names}";
treefmt-check> -      attr.${lib.head names};
treefmt-check> +    assert lib.assertMsg (lib.length names == 1)
treefmt-check> +      "attribute set doesn't contain just one attribute, instead it contains: ${lib.concatStringsSep ", " names}";
treefmt-check> +    attr.${lib.head names};
treefmt-check>  
treefmt-check>    backendPort =
treefmt-check>      if (cfg.accessMode ? "fullyPrivate") then
error: build of '/nix/store/s5ykqhymqrq2hhahckh9w87qh1b8rvbj-treefmt-check.drv' on 'ssh-ng://customer@mac02' failed: Cannot build '/nix/store/s5ykqhymqrq2hhahckh9w87qh1b8rvbj-treefmt-check.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/nihkknav60yx86zxly58g8gcr79ql2ml-treefmt-check
       Last 25 log lines:
       > emitted 91 files for processing
       > formatted 91 files (1 changed) in 2.713s
       >  M nixosModules/master.nix
       > diff --git a/nixosModules/master.nix b/nixosModules/master.nix
       > index 983beb2..5d72f7d 100644
       > --- a/nixosModules/master.nix
       > +++ b/nixosModules/master.nix
       > @@ -34,12 +34,14 @@ let
       >        ]
       >        name;
       >  
       > -  getAttrTag = attr:
       > +  getAttrTag =
       > +    attr:
       >      let
       >        names = lib.attrNames attr;
       >      in
       > -      assert lib.assertMsg (lib.length names == 1) "attribute set doesn't contain just one attribute, instead it contains: ${lib.concatStringsSep ", " names}";
       > -      attr.${lib.head names};
       > +    assert lib.assertMsg (lib.length names == 1)
       > +      "attribute set doesn't contain just one attribute, instead it contains: ${lib.concatStringsSep ", " names}";
       > +    attr.${lib.head names};
       >  
       >    backendPort =
       >      if (cfg.accessMode ? "fullyPrivate") then
       For full logs, run:
         nix log /nix/store/s5ykqhymqrq2hhahckh9w87qh1b8rvbj-treefmt-check.drv
error: Cannot build '/nix/store/s5ykqhymqrq2hhahckh9w87qh1b8rvbj-treefmt-check.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/nihkknav60yx86zxly58g8gcr79ql2ml-treefmt-check