public V remove(K key) {
    	
        RedBlackNode<K,V> node = findFirstNode(key);
        if (node == null) {
            return null;
        }
        V value = node.value;
        deleteEntry(node);
        return value;
    }
Removes the given key (first if duplicates are allowed) from the set.
@param key the key to remove from the set.
@return the value associated with the key removed or null if the key not found.
Ghidra/Framework/Generic/src/main/java/generic/stl/RedBlackTree.java