diff --git a/fab_access/mqtt_client.py b/fab_access/mqtt_client.py
index 337de9b..c65a759 100644
--- a/fab_access/mqtt_client.py
+++ b/fab_access/mqtt_client.py
@@ -5,12 +5,6 @@ import random
 import string
 
 class MqttHandler:
-    @staticmethod
-    def get_random_string(length):
-        # choose from all lowercase letter
-        letters = string.ascii_lowercase
-        result_str = ''.join(random.choice(letters) for i in range(length))
-        return(result_str)
 
     @staticmethod
     def setup(msg_handler):
@@ -25,7 +19,13 @@ class MqttHandler:
             else:
                 print('Failed to connect, return code %d\n', rc)
 
-        MqttHandler.client = mqtt_client.Client(Config.mqtt_client_id+MqttHandler.get_random_string(5))
+        def get_random_string(length):
+            # choose from all lowercase letter
+            letters = string.ascii_lowercase
+            result_str = ''.join(random.choice(letters) for i in range(length))
+            return(result_str)
+
+        MqttHandler.client = mqtt_client.Client(Config.mqtt_client_id+get_random_string(5))
         MqttHandler.client.username_pw_set('admin', 'user')
         MqttHandler.client.on_connect = on_connect
         MqttHandler.client.username_pw_set(Config.mqtt_user_name, Config.mqtt_password)