diff --git a/pkgs/development/python-modules/gin-config/default.nix b/pkgs/development/python-modules/gin-config/default.nix
index d1852a1392af..70e79eeebbb6 100644
--- a/pkgs/development/python-modules/gin-config/default.nix
+++ b/pkgs/development/python-modules/gin-config/default.nix
@@ -18,7 +18,7 @@ buildPythonPackage rec {
 
   };
 
-  propogatedBuildInputs = [ six enum34 ] + lib.optional withTensorflow tensorflow;
+  propogatedBuildInputs = [ six enum34 ] ++ lib.optional withTensorflow tensorflow;
   checkInputs = [ absl-py tensorflow ];
 
   meta = with lib; {