     "metadata": {},
     "source": [
      "## Test Cases\n",
      "\n",
      "* 5, 3, 8, 1, 4 -> Yes\n",
      "* 5, 3, 8, 9, 10 -> No"
     ]
    },
 
</s> remove     "def __check_balance__(root):\n",
 </s> add     "def _check_balance(root):\n",
    "* None -> No\n",
    "* 1 -> Yes\n",
     "metadata": {},
     "source": [
      "## Test Cases\n",
      "\n",
    "* None -> No\n",
    "* 1 -> Yes\n",
      "* 5, 3, 8, 1, 4 -> Yes\n",
      "* 5, 3, 8, 9, 10 -> No"
     ]
    },
keep keep keep add 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