          in_order_traversal(node, self.results.add_result)
          assert_equal(str(self.results), '[1, 2, 3, 5, 8]')
          self.results.clear_results()
  
          node = Node(1)
          insert(node, 2)
          insert(node, 3)
          insert(node, 4)
          insert(node, 5)
          in_order_traversal(node, self.results.add_result)
 
</s> remove     "        node = Node(1)\n",
 </s> add     "        node = insert(None, 1)\n", </s> remove     "        node = Node(1)\n",
 </s> add     "        node = insert(None, 1)\n", </s> remove     "* 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5"
 </s> add     "* 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5\n",
    "\n",
    "If the `root` input is `None`, return a tree with the only element being the new root node." </s> remove     "* 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5"
 </s> add     "* 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5\n",
    "\n",
    "If the `root` input is `None`, return a tree with the only element being the new root node."
        node = insert(None, 1)
          in_order_traversal(node, self.results.add_result)
          assert_equal(str(self.results), '[1, 2, 3, 5, 8]')
          self.results.clear_results()
  
        node = insert(None, 1)
          insert(node, 2)
          insert(node, 3)
          insert(node, 4)
          insert(node, 5)
          in_order_traversal(node, self.results.add_result)
keep keep keep keep replace keep keep keep keep keep
 Polish bst challenge and solution

Add root is None input test case.  Update time and space complexity discussion. 
graphs_trees/bst/test_bst.py