      "*Problem statements are sometimes ambiguous.  Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
      "\n",
      "* If there is one item in the list, do you expect the first and last pointers to both point to it?\n",
      "    * Yes\n",
      "* If there are no items on the list, do you expect the first and last pointers to be NULL?\n",
      "    * Yes\n",
      "* If you dequeue on an empty queue, does that return None?\n",
      "    * Yes"
     ]
    },
 
</s>
    "* If there are no items on the list, do you expect the first and last pointers to be None?\n",
      "*Problem statements are sometimes ambiguous.  Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
      "\n",
      "* If there is one item in the list, do you expect the first and last pointers to both point to it?\n",
      "    * Yes\n",
    "* If there are no items on the list, do you expect the first and last pointers to be None?\n",
      "    * Yes\n",
      "* If you dequeue on an empty queue, does that return None?\n",
      "    * Yes"
     ]
    },
keep keep keep keep replace keep keep keep keep keep
 Cleared queue challenge code section.  Changed references from NULL to None to be more Pythonic.
stacks_queues/queue_list/queue_list_solution.ipynb