    }
   ],
   "metadata": {
    "kernelspec": {
     "display_name": "Python 2",
     "language": "python",
     "name": "python2"
    },
    "language_info": {
     "codemirror_mode": {
 
</s> remove     "version": 2
 </s> add     "version": 3 </s> remove    "pygments_lexer": "ipython2",
   "version": "2.7.10"
 </s> add    "pygments_lexer": "ipython3",
   "version": "3.4.3" </s> remove     "* Pop on a one element stack to destroy it"
 </s> add     "* Pop on a stack to destroy it" </s> remove     "            if num_stacks == 0:\n",
    "                self.last_stack = None\n",
    "            else:\n",
    "                self.last_stack = self.stacks[num_stacks-1]\n",
    "        else:\n",
    "            data = self.last_stack.pop()\n",
 </s> add  </s> remove       "Test: Pop on a one element stack to destroy it\n",
 </s> add       "Test: Pop on a stack to destroy it\n",
   "display_name": "Python 3",
    }
   ],
   "metadata": {
    "kernelspec": {
   "display_name": "Python 3",
     "language": "python",
     "name": "python2"
    },
    "language_info": {
     "codemirror_mode": {
keep keep keep keep replace keep keep keep keep keep
 Polish set of stacks solution 
stacks_queues/set_of_stacks/set_of_stacks_solution.ipynb