def test_insert_already_existing_value(self): """ Insert already existing value Successfully """ red_black_tree = RedBlackTree() red_black_tree.insert(5) red_black_tree.insert(6) red_black_tree.insert(7) red_black_tree.insert(8) red_black_tree.insert(9) searching_elem = 9 red_black_tree.insert(searching_elem) num_of_necessary_nodes = 0 list_of_nodes = red_black_tree.travers_tree("LNR") for val in list_of_nodes: if val == searching_elem: num_of_necessary_nodes += 1 assert num_of_necessary_nodes == 1