diff --git a/manifests/master.pp b/manifests/master.pp
index 4bcf60c..bf8f4e2 100644
--- a/manifests/master.pp
+++ b/manifests/master.pp
@@ -16,7 +16,7 @@
   $manage_package = true,
   $ensure         = 'present',
 ) {
-  validate_legacy("NotUndef[String]", "validate_re", "${ensure}", ["."])
+  validate_legacy('NotUndef[String]', 'validate_re', $ensure, ['.'])
 
   include ::kubernetes::client