diff --git a/MQTT.py b/MQTT.py
index db3c92c..3747954 100644
--- a/MQTT.py
+++ b/MQTT.py
@@ -28,7 +28,7 @@ def valid(msg, client):
 
 # Message receiving callback
 def on_message(client, userdata, msg):
-    if valid(msg, client) is False:
+    if not valid(msg, client):
         return
     try:
         origin_data = json.loads(msg.payload.decode('utf-8'))