     "metadata": {},
     "source": [
      "## Constraints\n",
      "\n",
      "* Do you expect the methods to be enqueue and dequeue?\n",
      "    * Yes\n",
      "* Can we assume we already have a stack class that can be used for this problem?\n",
      "    * Yes"
     ]
    },
 
</s> remove     "* Do you expect the methods to be enqueue and dequeue?\n",
 </s> add     "* Do we expect the methods to be enqueue and dequeue?\n", </s> remove     "* If the left stack is empty and the right stack is not empty\n",
 </s> add     "* If right stack is not empty\n", </s> remove     "* If the right stack is empty and the the left stack is not empty\n",
 </s> add     "* If the left stack is not empty\n",
    "* Do we expect the methods to be enqueue and dequeue?\n",
     "metadata": {},
     "source": [
      "## Constraints\n",
      "\n",
    "* Do we expect the methods to be enqueue and dequeue?\n",
      "    * Yes\n",
      "* Can we assume we already have a stack class that can be used for this problem?\n",
      "    * Yes"
     ]
    },
keep keep keep keep replace keep keep keep keep keep
 Polish queue from stacks challenge and solution (#74)

Update constraints, algorithm discussion, and code. 
stacks_queues/queue_from_stacks/queue_from_stacks_challenge.ipynb