private function addCommonPropertiesFromArray(array $data)
    {
        $k                 = array_keys($data);
        $k                 = $k[0];
        $this->_result[$k] = [];
        foreach ($data[$k] as $c) {
            $id = $c['_id'];
            unset($c['_id']);
            $this->_result[$k][$id] = $c;
        }
    }