diff --git a/scripts/nbhelper/tenant.py b/scripts/nbhelper/tenant.py
index 4d529a7..a4d4048 100644
--- a/scripts/nbhelper/tenant.py
+++ b/scripts/nbhelper/tenant.py
@@ -6,7 +6,9 @@
 # tenant.py
 # The tenant abstract object of Netbox Object - Tenant
 
-from .utils import logger, netboxapi
+import sys
+
+from .utils import logger
 from .device import Device, VirtualMachine
 from .network import Prefix
 
@@ -58,9 +60,9 @@
         """
 
         for machine in self.devices + self.vms:
-            if name and machine.name == name:
-                return machine
-            elif machine.data["device_role"]["name"] == "Router":
+            if (name and machine.name == name) or machine.data["device_role"][
+                "name"
+            ] == "Router":
                 return machine
 
         ret_msg = (
@@ -71,10 +73,12 @@
         logger.error(ret_msg, name)
         sys.exit(1)
 
-    def get_devices(self, device_types=["server", "router"]):
+    def get_devices(self, device_types=None):
         """
         Get all devices (Router + Server) belong to this Tenant
         """
+        if not device_types:
+            device_types = ["server", "router"]
 
         if not device_types:
             return self.devices + self.vms