diff --git a/xos/synchronizer/models/models.py b/xos/synchronizer/models/models.py
new file mode 100644
index 0000000..108de2f
--- /dev/null
+++ b/xos/synchronizer/models/models.py
@@ -0,0 +1,41 @@
+
+# Copyright 2017-present Open Networking Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from xos.exceptions import *
+from models_decl import *
+
+class VSGServiceInstance(VSGServiceInstance_decl):
+    class Meta:
+        proxy = True
+
+    def __init__(self, *args, **kwargs):
+        super(VSGServiceInstance, self).__init__(*args, **kwargs)
+
+    def save(self, *args, **kwargs):
+        if not self.creator:
+            if not getattr(self, "caller", None):
+                # caller must be set when creating a vCPE since it creates a slice
+                raise XOSProgrammingError("VSGServiceInstance's self.caller was not set")
+            self.creator = self.caller
+            if not self.creator:
+                raise XOSProgrammingError("VSGServiceInstance's self.creator was not set")
+
+        super(VSGServiceInstance, self).save(*args, **kwargs)
+
+class VSGService(VSGService_decl):
+    class Meta:
+        proxy = True
+
+    pass