      "collapsed": false
     },
     "outputs": [],
     "source": [
      "def unique_chars(string):\n",
      "    if string is None:\n",
      "        return False\n",
      "    return len(set(string)) == len(string)"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
 
</s> remove     "def unique_chars_inplace(string):\n",
    "    if string is None:\n",
    "        return False\n",
    "    for char in string:\n",
    "        if string.count(char) > 1:\n",
 </s> add     "class UniqueCharsInPlace(object):\n",
    "\n",
    "    def has_unique_chars(self, string):\n",
    "        if string is None:\n", </s> remove     "def unique_chars_hash(string):\n",
    "    if string is None:\n",
    "        return False\n",
    "    chars_set = set()\n",
    "    for char in string:\n",
    "        if char in chars_set:\n",
 </s> add     "class UniqueChars(object):\n",
    "\n",
    "    def has_unique_chars(self, string):\n",
    "        if string is None:\n", </s> remove     "def unique_chars(string):\n",
    "    # TODO: Implement me\n",
    "    pass"
 </s> add     "class UniqueChars(object):\n",
    "\n",
    "    def has_unique_chars(self, string):\n",
    "        # TODO: Implement me\n",
    "        pass" </s> remove     "    return True"
 </s> add     "        for char in string:\n",
    "            if string.count(char) > 1:\n",
    "                return False\n",
    "        return True" </s> remove     "        else:\n",
    "            chars_set.add(char)\n",
    "    return True"
 </s> add     "        chars_set = set()\n",
    "        for char in string:\n",
    "            if char in chars_set:\n",
    "                return False\n",
    "            else:\n",
    "                chars_set.add(char)\n",
    "        return True"
    "class UniqueCharsSet(object):\n",
    "\n",
    "    def has_unique_chars(self, string):\n",
    "        if string is None:\n",
    "            return False\n",
    "        return len(set(string)) == len(string)"
      "collapsed": false
     },
     "outputs": [],
     "source": [
    "class UniqueCharsSet(object):\n",
    "\n",
    "    def has_unique_chars(self, string):\n",
    "        if string is None:\n",
    "            return False\n",
    "        return len(set(string)) == len(string)"
    "class UniqueCharsSet(object):\n",
    "\n",
    "    def has_unique_chars(self, string):\n",
    "        if string is None:\n",
    "            return False\n",
    "        return len(set(string)) == len(string)"
    "class UniqueCharsSet(object):\n",
    "\n",
    "    def has_unique_chars(self, string):\n",
    "        if string is None:\n",
    "            return False\n",
    "        return len(set(string)) == len(string)"
    "class UniqueCharsSet(object):\n",
    "\n",
    "    def has_unique_chars(self, string):\n",
    "        if string is None:\n",
    "            return False\n",
    "        return len(set(string)) == len(string)"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
keep keep keep keep replace replace replace replace keep keep keep keep keep
 Move unique chars to a class 
arrays_strings/unique_chars/unique_chars_solution.ipynb