     },
     "outputs": [],
     "source": [
      "def unique_chars(string):\n",
      "    return len(set(string)) == len(string)"
     ]
    },
    {
     "cell_type": "code",
     "execution_count": null,
     "metadata": {
      "collapsed": false
     },
     "outputs": [],
     "source": [
      "from nose.tools import assert_equal\n",
      "\n",
      "class Test(object):\n",
      "  def test_unique_chars(self):\n",
      "        assert_equal(unique_chars(''), True)\n",
      "        assert_equal(unique_chars('foo'), False)\n",
      "        assert_equal(unique_chars('bar'), True)    \n",
      "\n",
      "def run_tests():\n",
      "    test = Test()\n",
      "    test.test_unique_chars()\n",
      "\n",
      "run_tests()"
     ]
    },
    {
 
</s> remove     "run_tests()"
 </s> add     "run_tests(unique_chars)" </s> remove     "def unique_chars_alt(string):\n",
 </s> add     "def unique_chars_inplace(string):\n", </s> remove     "run_tests()"
 </s> add     "run_tests(unique_chars_hash)" </s> remove     "def unique_chars_alt(string):\n",
 </s> add     "def unique_chars_hash(string):\n",
    "    return len(set(string)) == len(string)\n",
     },
     "outputs": [],
     "source": [
      "def unique_chars(string):\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
    "    return len(set(string)) == len(string)\n",
      "\n",
      "run_tests()"
     ]
    },
    {
keep keep keep keep replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace replace keep keep keep keep keep
 Moved unit test to test case section.  Updated unit test to take a function parameter on which to run the test. 
arrays-strings/unique_chars.ipynb