      "class MyStack(Stack):\n",
      "\n",
      "    def __init__(self, top=None):\n",
      "        self.min_vals = Stack()\n",
      "        super(MyStack, self).__init__(top)\n",
      "\n",
      "    def min(self):\n",
      "        if self.min_vals.top is None:\n",
      "            return sys.maxsize\n",
      "        else:\n",
 
</s> remove     "class MyStack(Stack):\n",
 </s> add     "class StackMin(Stack):\n", </s> remove     "        super(MyStack, self).push(data)\n",
 </s> add     "        super(StackMin, self).push(data)\n", </s> remove     "class MyStack(Stack):\n",
 </s> add     "class StackMin(Stack):\n", </s> remove     "        data = super(MyStack, self).pop()\n",
 </s> add     "        data = super(StackMin, self).pop()\n",
      "class MyStack(Stack):\n",
      "\n",
      "    def __init__(self, top=None):\n",
      "        self.min_vals = Stack()\n",

      "\n",
      "    def min(self):\n",
      "        if self.min_vals.top is None:\n",
      "            return sys.maxsize\n",
      "        else:\n",
keep keep keep keep replace keep keep keep keep keep
 Polish stack min challenge and solution (#72)

Update constraints, algorithm discussion, code, and tests. 
stacks_queues/stack_min/stack_min_solution.ipynb