code: public function getPermissionsByRole($roleName)
      {
          $childrenList = $this->getChildrenList();
          $result = [];
          $this->getChildrenRecursive($roleName, $childrenList, $result);
          if (empty($result)) {
              return [];
          }
          $query = (new Query())->from($this->itemTable)->where([
              'type' => Item::TYPE_PERMISSION,
              'name' => array_keys($result),
          ]);
          $permissions = [];
          foreach ($query->all($this->db) as $row) {
              $permissions[$row['name']] = $this->populateItem($row);
          }
  
          return $permissions;
      }
docs: {@inheritdoc}