      "    def test_compress(self, func):\n",
      "        assert_equal(func(None), None)\n",
      "        assert_equal(func(''), '')\n",
      "        assert_equal(func('AABBCC'), 'AABBCC')\n",
      "        assert_equal(func('AAABCCDDDD'), 'A3B1C2D4')\n",
      "        print('Success: test_compress')\n",
      "\n",
      "\n",
      "def main():\n",
      "    test = TestCompress()\n",
 
</s> remove     "* 'AAABCCDDDD' -> 'A3B1C2D4'"
 </s> add     "* 'AAABCCDDDD' -> 'A3BCCD4'" </s> remove     "## Problem: Compress a string such that 'AAABCCDDDD' becomes 'A3B1C2D4'.  Only compress the string if it saves space.\n",
 </s> add     "## Problem: Compress a string such that 'AAABCCDDDD' becomes 'A3BCCD4'.  Only compress the string if it saves space.\n", </s> remove    "pygments_lexer": "ipython2",
   "version": "2.7.10"
 </s> add    "pygments_lexer": "ipython3",
   "version": "3.4.3" </s> remove     "version": 2
 </s> add     "version": 3 </s> remove    "name": "python2"
 </s> add    "name": "python3"
    "        assert_equal(func('AAABCCDDDD'), 'A3BCCD4')\n",
      "    def test_compress(self, func):\n",
      "        assert_equal(func(None), None)\n",
      "        assert_equal(func(''), '')\n",
      "        assert_equal(func('AABBCC'), 'AABBCC')\n",
    "        assert_equal(func('AAABCCDDDD'), 'A3BCCD4')\n",
      "        print('Success: test_compress')\n",
      "\n",
      "\n",
      "def main():\n",
      "    test = TestCompress()\n",
keep keep keep keep replace keep keep keep keep keep
 Added the same changes to test cases in the challenge notebook 
arrays_strings/compress/compress_challenge.ipynb