fix default for provider_service
diff --git a/xos/core/xoslib/methods/volttenant.py b/xos/core/xoslib/methods/volttenant.py
index c3b2dbc..356938e 100644
--- a/xos/core/xoslib/methods/volttenant.py
+++ b/xos/core/xoslib/methods/volttenant.py
@@ -26,7 +26,7 @@
         id = ReadOnlyField()
         service_specific_id = serializers.CharField()
         vlan_id = serializers.CharField()
-        provider_service = serializers.PrimaryKeyRelatedField(queryset=VOLTService.get_service_objects().all(), default=get_default_volt_service())
+        provider_service = serializers.PrimaryKeyRelatedField(queryset=VOLTService.get_service_objects().all(), default=get_default_volt_service)
 
         humanReadableName = serializers.SerializerMethodField("getHumanReadableName")