diff --git a/octoprint_enclosure/__init__.py b/octoprint_enclosure/__init__.py
index cf4fdcb..531335b 100644
--- a/octoprint_enclosure/__init__.py
+++ b/octoprint_enclosure/__init__.py
@@ -100,12 +100,12 @@ class EnclosurePlugin(octoprint.plugin.StartupPlugin,
 
     @octoprint.plugin.BlueprintPlugin.route("/getOutputStatus", methods=["GET"])
     def getOutputStatus(self):
-        getOutputStatusresult = ""
+        getOutputStatusresult = ''
         for rpi_output in self.rpi_outputs:
             pin = self.toInt(rpi_output['gpioPin'])
             if rpi_output['outputType']=='regular':
                 val = GPIO.input(pin) if not rpi_output['activeLow'] else (not GPIO.input(pin))
-                getOutputStatusresult = getOutputStatusresult pin + ":" + val + ","
+                getOutputStatusresult = getOutputStatusresult + str(pin) + ':' + str(val) + ','
         return getOutputStatusresult