Upgrading inv.objectmodels
    ... upgrading Cisco | 7600 | RSP720-3CXL-GE
ERROR:root:UNHANDLED EXCEPTION (2014-06-04 11:39:58.879127)
Working directory: /opt/noc
<class 'mongoengine.base.ValidationError'>
Unable to dereference <class 'noc.inv.models.vendor.Vendor'>:5319b28a4a5e6844c85d54ae
START OF TRACEBACK
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File: /opt/noc/lib/nosql.py (Line: 105)
Function: __get__
   98             # Dereference DBRefs
   99             if isinstance(value, ObjectId):
  100                 v = self.document_type.objects(id=value).first()
  101                 if v is not None:
  102                     instance._data[self.name] = v
  103                 else:
  104                     raise ValidationError("Unable to dereference %s:%s" % (
  105 ==>                     self.document_type, value))
  106             return super(PlainReferenceField, self).__get__(instance, owner)
  107
  108         def to_mongo(self, document):
  109             if isinstance(document, Document):
  110                 # We need the id from the saved object to create the DBRef
  111                 id_ = document.id
Variables:
               owner = <class 'noc.inv.models.objectmodel.ObjectModel'>
            instance = <ObjectModel: Cisco | 7600 | RSP720-3CXL-GE>
                self = <noc.lib.nosql.PlainReferenceField object at 0x32be4d0>
               value = ObjectId('5319b28a4a5e6844c85d54ae')
                   v = None
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