diff --git a/awsiot/__init__.py b/awsiot/__init__.py
index fbd5a084..8cd0f3f7 100644
--- a/awsiot/__init__.py
+++ b/awsiot/__init__.py
@@ -39,7 +39,7 @@ def __init__(self, mqtt_connection: mqtt.Connection or mqtt5.Client):
             self._mqtt_connection = mqtt_connection.new_connection()
             self._mqtt5_client = mqtt_connection
         else:
-            assert("The service client could only take mqtt.Connection and mqtt5.Client as argument")
+            raise TypeError("The service client could only take mqtt.Connection and mqtt5.Client as argument")
 
     @property
     def mqtt_connection(self) -> mqtt.Connection: