public void popEntries(int numberToRemove) {
        for (int i = 0; i < numberToRemove; i++) {
            Binder b = symbols.get(top);
            if (b.getTail() != null) {
                symbols.put(top, b.getTail());
            } else {
                symbols.remove(top);
            }
            top = b.getPreviousTop();
        }
    }