      "    * Push data to second stack\n",
      "\n",
      "Complexity:\n",
      "* Time: O(1)\n",
      "* Space: O(n)\n",
      "\n",
      "### Pop\n",
      "\n",
      "* Pop the data\n",
      "* If the data is equal to min\n",
 
</s> remove     "* If we call this function on an empty stack, can we return maxsize?\n",
 </s> add     "* Can we assume the input values for push are valid?\n",
    "    * Yes\n",
    "* If we call this function on an empty stack, can we return sys.maxsize?\n", </s> remove     "        data = super(MyStack, self).pop()\n",
 </s> add     "        data = super(StackMin, self).pop()\n",
    "* Space: O(1)\n",
      "    * Push data to second stack\n",
      "\n",
      "Complexity:\n",
      "* Time: O(1)\n",
    "* Space: O(1)\n",
      "\n",
      "### Pop\n",
      "\n",
      "* Pop the data\n",
      "* If the data is equal to min\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