pocketmine\level\generator\biome\Biome::init PHP Method

    public static function init()
    {
        self::register(self::OCEAN, new OceanBiome());
        self::register(self::PLAINS, new PlainBiome());
        self::register(self::DESERT, new DesertBiome());
        self::register(self::MOUNTAINS, new MountainsBiome());
        self::register(self::FOREST, new ForestBiome());
        self::register(self::TAIGA, new TaigaBiome());
        self::register(self::SWAMP, new SwampBiome());
        self::register(self::RIVER, new RiverBiome());
        self::register(self::ICE_PLAINS, new IcePlainsBiome());
        self::register(self::SMALL_MOUNTAINS, new SmallMountainsBiome());
        self::register(self::HELL, new HellBiome());
        self::register(self::BIRCH_FOREST, new ForestBiome(ForestBiome::TYPE_BIRCH));
    }

 public function onRun()
 {
     Block::init();
     Biome::init();
     $manager = new SimpleChunkManager($this->seed);
     $this->saveToThreadStore("generation.level{$this->levelId}.manager", $manager);
     /** @var Generator $generator */
     $generator = $this->generator;
     $generator = new $generator($this->settings);
     $generator->init($manager, new Random($manager->getSeed()));
     $this->saveToThreadStore("generation.level{$this->levelId}.generator", $generator);
 }