Fix issues loading demo data

netbox/dcim/signals.py

@@ -128,11 +128,11 @@ def nullify_connected_endpoints(instance, **kwargs):
 
 
 @receiver(post_save, sender=FrontPort)
-def extend_rearport_cable_paths(instance, created, **kwargs):
+def extend_rearport_cable_paths(instance, created, raw, **kwargs):
     """
     When a new FrontPort is created, add it to any CablePaths which end at its corresponding RearPort.
     """
-    if created:
+    if created and not raw:
         rearport = instance.rear_port
         for cablepath in CablePath.objects.filter(_nodes__contains=rearport):
             cablepath.retrace()

netbox/utilities/serializers/json.py

@@ -1,7 +1,9 @@
 from django.contrib.postgres.fields import ArrayField
-from django.core.serializers.json import Serializer as Serializer_
+from django.core.serializers.json import Deserializer, Serializer as Serializer_  # noqa
 from django.utils.encoding import is_protected_type
 
+# NOTE: Module must contain both Serializer and Deserializer
+
 
 class Serializer(Serializer_):
     """