          with captured_output() as (out, err):
              root.post_order_traversal(sys.stdout.write)
              assert_equal(out.getvalue().strip(), '13285')
  
          with captured_output() as (out, err):
              root.bfs(sys.stdout.write)
              assert_equal(out.getvalue().strip(), '52813')
  
          root = Node(1)
          root.insert(2)
          root.insert(3)
          root.insert(4)
          root.insert(5)
 
</s> remove     "        with captured_output() as (out, err):\n",
    "            root.bfs(sys.stdout.write)\n",
    "            assert_equal(out.getvalue().strip(), '52813')\n",
    "\n",
 </s> add  </s> remove     "        with captured_output() as (out, err):\n",
    "            root.bfs(sys.stdout.write)\n",
    "            assert_equal(out.getvalue().strip(), '52813')\n",
    "\n",
 </s> add  </s> remove    "execution_count": 5,
 </s> add    "execution_count": 4, </s> remove    "execution_count": 4,
 </s> add    "execution_count": 3, </s> remove    "execution_count": 3,
 </s> add    "execution_count": 2,
          with captured_output() as (out, err):
              root.post_order_traversal(sys.stdout.write)
              assert_equal(out.getvalue().strip(), '13285')
  




          root = Node(1)
          root.insert(2)
          root.insert(3)
          root.insert(4)
          root.insert(5)
keep keep keep keep replace replace replace replace keep keep keep keep keep
 Revised dfs challenge to be more self contained for simplicity. 
graphs_trees/tree_dfs/test_dfs.py