def get_next_id(self):
        try:
            query = {'_id': 'last_id'}
            update = {'$inc': {'id': 1}}
            fn = self.db.internal.find_and_modify
            row = fn(query, update, upsert=True, new=True)
        except Exception as e:
            raise DatabaseException(e)
        return row['id']
def process_weight(sym, arg, aux):
            for stride in RpnParam.anchor_generate.stride:
                add_anchor_to_arg(
                    sym, arg, aux, RpnParam.anchor_generate.max_side,
                    stride, RpnParam.anchor_generate.scale,
                    RpnParam.anchor_generate.ratio)