text: #include <iostream>
  #include "RedBlackTree.h"
  
  using namespace std;
  
  int main() {
      RedBlackTree<int> tree;
      tree.insert(5);
      tree.insert(3);
      tree.insert(2);
      tree.insert(8);
      tree.insert(10);
      tree.insert(9);
      cout << tree.contains(1) << endl;
      cout << tree.contains(10) << endl;
      cout << tree.contains(9) << endl;
      cout << tree.contains(4) << endl;
  }
  