pocketmine\level\Level::getSeed PHP Method

    public function getSeed()
    {
        return $this->provider->getSeed();
    }

 public function __construct(Level $level, Generator $generator)
 {
     $this->generator = get_class($generator);
     $this->settings = $generator->getSettings();
     $this->seed = $level->getSeed();
     $this->levelId = $level->getId();
 }