diff --git a/pkgs/development/python-modules/natsort/default.nix b/pkgs/development/python-modules/natsort/default.nix
index fc80f30aadc859..bfe486e1a54abb 100644
--- a/pkgs/development/python-modules/natsort/default.nix
+++ b/pkgs/development/python-modules/natsort/default.nix
@@ -8,6 +8,7 @@
 , hypothesis
 , glibcLocales
 , pathlib ? null
+, isPy3k
 }:
 
 buildPythonPackage rec {