public void load(NBTTagCompound nbttagcompound) {
        this.position = new BlockPosition(nbttagcompound.getInt("x"), nbttagcompound.getInt("y"), nbttagcompound.getInt("z"));
        // CraftBukkit start - read container
        NBTTagCompound persistentDataTag = nbttagcompound.getCompound("PublicBukkitValues");
        if (persistentDataTag != null) {
            this.persistentDataContainer.clear(); // This call would remove all old values from the container
            this.persistentDataContainer.putAll(persistentDataTag);
        }
        // CraftBukkit end
    }

public void clear() { // Note that this method does not exist yet as till now the DataContainer instances were passed to the API directly from their NMS owner and never had to be "updated" against a different version of themselves.
        this.customDataTags.clear();    
}