class RedBlackTree {

    public boolean containsKey(K key) {

	    RedBlackNode<K,V> node = root;
        while(node != null) {
        	int comp = comparator.compare(key, node.key);
            if (comp == 0 ){
                return true;
            }
            if (comp < 0) {
                node = node.left;
            }
            else {
                node = node.right;
            }
        }
        return false;
    }

    public  RedBlackTree(Comparator<K> comparator, boolean allowDuplicateKeys);
    public  RedBlackTree(RedBlackTree<K, V> tree);

}