diff --git a/manifests/init.pp b/manifests/init.pp
index 0cf2a43..243706d 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -299,7 +299,7 @@
         uid                          =>  $uid,
         week_days                    =>  $week_days,
         zone                         =>  $zone,
-      }
+      }.filter |$_key, $val| { $val =~ NotUndef }
     }
   )