pocketmine\Server::getLevelByName PHP Method

    public function getLevelByName($name)
    {
        foreach ($this->getLevels() as $level) {
            if ($level->getFolderName() === $name) {
                return $level;
            }
        }
        return null;
    }

 /**
  * Get a world name and return a level object.  Loads levels as needed
  *
  * @param Server $server
  * @param str $world
  * @return Level|null
  */
 public static function getLevelByName(Server $server, $world)
 {
     if (!$server->isLevelGenerated($world)) {
         return null;
     }
     if (!$server->isLevelLoaded($world)) {
         $server->loadLevel($world);
     }
     return $server->getLevelByName($world);
 }