-> wx.GetApp().UIRepositoryView.commit()
  /Users/grant/src/chandler/repository/persistence/DBRepositoryView.py(592)commit()
-> self.effectDelete()
  /Users/grant/src/chandler/repository/item/Item.py(1505)_effectDelete()
-> delattr(self, name)
  /Users/grant/src/chandler/repository/item/Item.py(529)removeAttributeValue()
-> _attrDict._removeValue(name, value, otherName)
  /Users/grant/src/chandler/repository/item/Values.py(542)_removeValue()
-> otherKey = self._removeRef(name, other, dictKey)
  /Users/grant/src/chandler/repository/item/Values.py(560)_removeRef()
-> other.clear()
  /Users/grant/src/chandler/repository/item/RefCollections.py(299)clear()
-> self.remove(other)
  /Users/grant/src/chandler/repository/item/RefCollections.py(431)remove()
-> self._otherName, self._dictKey)
  /Users/grant/src/chandler/repository/item/Values.py(545)_removeValue()
-> other._references._removeRef(otherName, item, otherKey)
  /Users/grant/src/chandler/repository/item/Values.py(578)_removeRef()
-> item._fireChanges('remove', name)
> /Users/grant/src/chandler/parcels/osaf/pim/calendar/Calendar.py(2497)occurrenceForChanged()->None
-> import pdb; pdb.set_trace()