diff --git a/arrays-strings/unique_chars.ipynb b/arrays-strings/unique_chars.ipynb
index 2af80af..21d5a62 100644
--- a/arrays-strings/unique_chars.ipynb
+++ b/arrays-strings/unique_chars.ipynb
@@ -45,6 +45,27 @@
     "* 'bar' -> True"
    ]
   },
+  {
+   "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, func):\n",
+    "        assert_equal(func(''), True)\n",
+    "        assert_equal(func('foo'), False)\n",
+    "        assert_equal(func('bar'), True)\n",
+    "\n",
+    "def run_tests(func):\n",
+    "    test = Test()\n",
+    "    test.test_unique_chars(func)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -79,30 +100,9 @@
    "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",
+    "    return len(set(string)) == len(string)\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()"
+    "run_tests(unique_chars)"
    ]
   },
   {
@@ -144,7 +144,7 @@
    },
    "outputs": [],
    "source": [
-    "def unique_chars_alt(string):\n",
+    "def unique_chars_hash(string):\n",
     "    chars_set = set()\n",
     "    for char in string:\n",
     "        if char in chars_set:\n",
@@ -153,7 +153,7 @@
     "            chars_set.add(char)\n",
     "    return True\n",
     "\n",
-    "run_tests()"
+    "run_tests(unique_chars_hash)"
    ]
   },
   {
@@ -190,13 +190,13 @@
    },
    "outputs": [],
    "source": [
-    "def unique_chars_alt(string):\n",
+    "def unique_chars_inplace(string):\n",
     "    for char in string:\n",
     "        if string.count(char) > 1:\n",
     "            return False\n",
     "    return True\n",
     "\n",
-    "run_tests()"
+    "run_tests(unique_chars_inplace)"
    ]
   }
  ],