private void deleteCase3(RBTreeNode<K,V> node) {
        //If parent, sibling, and both sibling's children are black
        if (nodeColor(node.parent) == Color.BLACK &&
                nodeColor(node.sibling()) == Color.BLACK &&
                nodeColor(node.sibling().left) == Color.BLACK &&
                nodeColor(node.sibling().right) == Color.BLACK) {
            //Paint sibling red, and fix properties from sibling's parent.
            node.sibling().color = Color.RED;
            deleteCase1(node.parent);
        } else {
            deleteCase4(node);
        }
    }