yii\mongodb\rbac\MongoDbManager::getItem PHP Method

    protected function getItem($name)
    {
        if (empty($name)) {
            return null;
        }
        if (!empty($this->items[$name])) {
            return $this->items[$name];
        }
        $row = (new Query())->from($this->itemCollection)->where(['name' => $name])->one($this->db);
        if ($row === false) {
            return null;
        }
        return $this->populateItem($row);
    }