diff --git a/pkgs/development/python-modules/schema-salad/default.nix b/pkgs/development/python-modules/schema-salad/default.nix
index c1a2295ec88b..16d6c6120da1 100644
--- a/pkgs/development/python-modules/schema-salad/default.nix
+++ b/pkgs/development/python-modules/schema-salad/default.nix
@@ -38,7 +38,7 @@ buildPythonPackage rec {
     rdflib
     ruamel-yaml
     setuptools # needs pkg_resources at runtime
-  ];
+  ] ++ cachecontrol.optional-dependencies.filecache;
 
   nativeCheckInputs = [
     pytestCheckHook