Upgrading inv.objectmodels
    ... upgrading Cisco | ME3400E | ME-3400EG-12CS-M
Traceback (most recent call last):
  File "manage.py", line 44, in <module>
    execute_from_command_line(sys.argv)
  File "/opt/noc/lib/python2.7/site-packages/django/core/management/__init__.py", line 443, in execute_from_command_line
    utility.execute()
  File "/opt/noc/lib/python2.7/site-packages/django/core/management/__init__.py", line 382, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/opt/noc/lib/python2.7/site-packages/django/core/management/base.py", line 196, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/opt/noc/lib/python2.7/site-packages/django/core/management/base.py", line 232, in execute
    output = self.handle(*args, **options)
  File "/opt/noc/main/management/commands/collection.py", line 85, in handle
    return self.handle_sync()
  File "/opt/noc/main/management/commands/collection.py", line 110, in handle_sync
    lc.apply(dc)
  File "/opt/noc/lib/collection.py", line 130, in apply
    self.upgrade_collection(collection)
  File "/opt/noc/lib/collection.py", line 312, in upgrade_collection
    upgrade_item(u)
  File "/opt/noc/lib/collection.py", line 302, in upgrade_item
    o.save()
  File "/opt/noc/inv/models/objectmodel.py", line 109, in save
    super(ObjectModel, self).save(*args, **kwargs)
  File "/opt/noc/lib/python2.7/site-packages/mongoengine/document.py", line 184, in save
    self.validate()
  File "/opt/noc/lib/python2.7/site-packages/mongoengine/base.py", line 891, in validate
    for name, field in self._fields.items()]
  File "/opt/noc/lib/nosql.py", line 103, in __get__
    self.document_type, value))
mongoengine.base.ValidationError: Unable to dereference <class 'noc.inv.models.vendor.Vendor'>:527d01daafc7cf168551db4b
upgrade-user: : collection --sync failed
Terminating
upgrade complete