@Override
    public void putAll(final Map<? extends String, ? extends V> map) {
        for (final Map.Entry<? extends String, ? extends V> entry : map.entrySet()) {
            put(convertKey(entry.getKey()), entry.getValue());
        }
    }

    @Override
    public final V remove(final Object key) {
        return super.remove(convertKey(key));
    }

    @Override
    public boolean containsKey(final Object key) {