/**
     * Check if the worker requires a certain amount of that item and if the deliveryman already kept it.
     * Always leave one stack behind if the worker requires a certain amount of it. Just to be sure.
     *
     * @param building         the building of the worker.
     * @param stack            the stack to check it with.
     * @param localAlreadyKept already kept items.
     * @return true if deliveryman should leave it behind.
     */
    private static boolean buildingRequiresCertainAmountOfItem(AbstractBuilding building, ItemStack stack, List<ItemStorage> localAlreadyKept)
    {
        for (final Map.Entry<ItemStorage, Integer> entry : building.getRequiredItemsAndAmount().entrySet())
        {
            if (entry.getKey().getItem() == stack.getItem()
                    && entry.getKey().getDamageValue() == stack.getItemDamage()
                    && !localAlreadyKept.contains(entry.getKey()))
            {
                localAlreadyKept.add(entry.getKey());
                return true;
            }
        }
        return false;
    }