Antes de actualizar

Sistemas/serializers.py

@@ -47,7 +47,7 @@ class DeviceSerializer(serializers.ModelSerializer):
             # A device with the same macAddress already exists for the given sistema and client
             # Get the number of existing devices and add 1 to create a new suffix
             suffix = existing_devices.count() + 1
-            mac_address += f'_{suffix}'        
+            mac_address += f'_{suffix}'
 
         validated_data['macAddress']= mac_address
         return super().create(validated_data)