      "        print('Test: 2 or more disks')\n",
      "        for i in xrange(num_disks, -1, -1):\n",
      "            src.push(i)\n",
      "        hanoi(num_disks, src, dest, buff)\n",
      "        for i in xrange(0, num_disks):\n",
      "            assert_equal(dest.pop(), i)\n",
      "\n",
      "        print('Success: test_hanoi')\n",
      "\n",
      "def main():\n",
 
</s> remove     "        for i in xrange(0, num_disks):\n",
 </s> add     "        for i in range(0, num_disks):\n", </s> remove     "        for i in xrange(num_disks, -1, -1):\n",
 </s> add     "        for i in range(num_disks, -1, -1):\n", </s> remove     "        for i in xrange(num_disks, -1, -1):\n",
 </s> add     "        for i in range(num_disks, -1, -1):\n", </s> remove         for i in xrange(num_disks, -1, -1):
 </s> add         for i in range(num_disks, -1, -1): </s> remove         for i in xrange(0, num_disks):
 </s> add         for i in range(0, num_disks):
    "        for i in range(0, num_disks):\n",
      "        print('Test: 2 or more disks')\n",
      "        for i in xrange(num_disks, -1, -1):\n",
      "            src.push(i)\n",
      "        hanoi(num_disks, src, dest, buff)\n",
    "        for i in range(0, num_disks):\n",
      "            assert_equal(dest.pop(), i)\n",
      "\n",
      "        print('Success: test_hanoi')\n",
      "\n",
      "def main():\n",
keep keep keep keep replace keep keep keep keep keep
 Changed xrange to range to be compatible with Python 3. 
stacks_queues/hanoi/hanoi_challenge.ipynb