      "class TestCheckBalance(object):\n",
      "\n",
      "    def test_check_balance(self):\n",
      "        node = Node(5)\n",
      "        assert_equal(check_balance(node), True)\n",
      "\n",
      "        insert(node, 3)\n",
      "        insert(node, 8)\n",
 
</s>
    "        assert_equal(check_balance(None), False)\n",
    "\n",
      "class TestCheckBalance(object):\n",
      "\n",
      "    def test_check_balance(self):\n",
    "        assert_equal(check_balance(None), False)\n",
    "\n",
      "        node = Node(5)\n",
      "        assert_equal(check_balance(node), True)\n",
      "\n",
      "        insert(node, 3)\n",
      "        insert(node, 8)\n",
keep keep add keep keep keep keep keep
 Polish check tree balance challenge and solution (#80)

Update constraints, test cases, tests, and code.
graphs_trees/check_balance/check_balance_challenge.ipynb