diff --git a/pkgs/development/python-modules/whichcraft/default.nix b/pkgs/development/python-modules/whichcraft/default.nix
index 7c7ac4e269ae..b237513ef0f5 100644
--- a/pkgs/development/python-modules/whichcraft/default.nix
+++ b/pkgs/development/python-modules/whichcraft/default.nix
@@ -16,7 +16,7 @@ buildPythonPackage rec {
     sha256 = "11yfkzyplizdgndy34vyd5qlmr1n5mxis3a3svxmx8fnccdvknxc";
   };
 
-  LC_ALL = "en_US.utf-8";
+  env.LC_ALL = "en_US.utf-8";
   buildInputs = [ glibcLocales ];
 
   nativeCheckInputs = [ pytest ];