public static void registerEntities() {
        for (CustomEntityType entity : values())
            a(entity.getCustomClass(), entity.getName(), entity.getID());

// BiomeBase#biomes became private.
        BiomeBase[] biomes;
        try {
            biomes = (BiomeBase[]) getPrivateStatic(BiomeBase.class, "biomes");
        } catch (Exception exc) {
// Unable to fetch.
            return;
        }
        for (BiomeBase biomeBase : biomes) {
            if (biomeBase == null)
                break;

// This changed names from J, K, L and M.
            for (String field : new String[]{"as", "at", "au", "av"})
                try {
                    Field list = BiomeBase.class.getDeclaredField(field);
                    list.setAccessible(true);
                    @SuppressWarnings("unchecked")
                    List<BiomeMeta> mobList = (List<BiomeMeta>) list.get(biomeBase);

// Write in our custom class.
                    for (BiomeMeta meta : mobList)
                        for (CustomEntityType entity : values())
                            if (entity.getNMSClass().equals(meta.b))
                                meta.b = entity.getCustomClass();
                } catch (Exception e) {
                    e.printStackTrace();
                }
        }
    }