def __property_config__(self, model_class, property_name):
    super(ReferenceProperty, self).__property_config__(model_class,
                                                       property_name)

    if self.reference_class is _SELF_REFERENCE:
      self.reference_class = self.data_type = model_class

    if self.collection_name is None:
      self.collection_name = '%s_set' % (model_class.__name__.lower())
    existing_prop = getattr(self.reference_class, self.collection_name, None)
    if existing_prop is not None:
      if not (isinstance(existing_prop, _ReverseReferenceProperty) and
              existing_prop._prop_name == property_name and
              existing_prop._model.__name__ == model_class.__name__ and
              existing_prop._model.__module__ == model_class.__module__):
        raise DuplicatePropertyError('Class %s already has property %s '
                                   % (self.reference_class.__name__,
                                      self.collection_name))
    setattr(self.reference_class,
            self.collection_name,
            _ReverseReferenceProperty(model_class, property_name))
Loads all of the references that point to this model.
dataset/ETHPy150Open CollabQ/CollabQ/.google_appengine/google/appengine/ext/db/__init__.py/ReferenceProperty.__property_config__