':rtype: ModelQuerySet'

def __get__(self, obj, model):

    if model.__abstract__:
        raise CQLEngineException('cannot    execute    queries    against    abstract    models')
    queryset = model.__queryset__(model)
    if (model._is_polymorphic and (not model._is_polymorphic_base)):
        (name, column) = (model._discriminator_column_name, model._discriminator_column)
        if (column.partition_key or column.index):
            return queryset.filter(**{name: model.__discriminator_value__})
    return queryset
