diff --git a/pkgs/development/python-modules/class-registry/default.nix b/pkgs/development/python-modules/class-registry/default.nix
index 9a3650bceb8b..93c41cadea6e 100644
--- a/pkgs/development/python-modules/class-registry/default.nix
+++ b/pkgs/development/python-modules/class-registry/default.nix
@@ -4,6 +4,8 @@
   lib,
   nose,
   six,
+  typing,
+  isPy27,
 }:
 
 buildPythonPackage rec {
@@ -15,7 +17,7 @@ buildPythonPackage rec {
     sha256 = "0zjf9nczl1ifzj07bgs6mwxsfd5xck9l0lchv2j0fv2n481xp2v7";
   };
 
-  propagatedBuildInputs = [ six ];
+  propagatedBuildInputs = [ six ] ++ lib.optional isPy27 typing;
   checkInputs = [ nose ];
 
   # Tests currently failing.