pythonPackages.premailer: fix build

(cherry picked from commit 1728793)

pkgs/development/python-modules/premailer/default.nix

@@ -1,22 +1,22 @@
 { lib, buildPythonPackage, fetchPypi,
-  cssselect, cssutils, lxml, mock, nose, requests
+  cssselect, cssutils, lxml, mock, nose, requests, cachetools
 }:
 
 buildPythonPackage rec {
   pname = "premailer";
   version = "3.3.0";
 
-  meta = {
-    description = "Turns CSS blocks into style attributes ";
-    homepage = https://github.com/peterbe/premailer;
-    license = lib.licenses.bsd3;
-  };
-
   src = fetchPypi {
     inherit pname version;
     sha256 = "93be4f197e9d2a87a8fe6b5b6a79b64070dbb523108dfaf2a415b4558fc78ec1";
   };
 
   buildInputs = [ mock nose ];
-  propagatedBuildInputs = [ cssselect cssutils lxml requests ];
+  propagatedBuildInputs = [ cachetools cssselect cssutils lxml requests ];
+
+  meta = {
+    description = "Turns CSS blocks into style attributes ";
+    homepage = https://github.com/peterbe/premailer;
+    license = lib.licenses.bsd3;
+  };
 }