Add an actual comma

manifests/firewall.pp

@@ -11,7 +11,7 @@ class puppet_cwsens::firewall{
 
   ::server_firewall::constricto_chain{'ipsum-mqtt': }
   ::server_firewall::rules_file { '55-permit-ipsum-mqtt.rules':
-    content => $mqtt_rule
+    content => $mqtt_rule,
     require => ::server_firewall::Constricto_chain['ipsum-mqtt'],
   }
 }