diff --git a/nixos/tests/installer.nix b/nixos/tests/installer.nix
index 3a561646ad90..21d5e1470d8e 100644
--- a/nixos/tests/installer.nix
+++ b/nixos/tests/installer.nix
@@ -511,7 +511,7 @@ let
             perlPackages.ListCompare
             perlPackages.XMLLibXML
             # make-options-doc/default.nix
-            python3.withPackages (p: [ p.mistune ])
+            (python3.withPackages (p: [ p.mistune ]))
             shared-mime-info
             sudo
             texinfo