diff --git a/01-data-model/README.md b/01-data-model/README.md
index 18e2865..bd6d547 100644
--- a/01-data-model/README.md
+++ b/01-data-model/README.md
@@ -1,25 +1,68 @@
-# The Python Data Model
+# Python 数据模型
 
-Sample code for Chapter 1 of _Fluent Python 2e_ by Luciano Ramalho (O'Reilly, 2020)
+_Luciano Ramalho 著《流畅的 Python（第2版）》（O'Reilly, 2020）_ 第一章的示例代码
 
-## Running the tests
+## 运行测试
 
-### Doctests
+### Doctest
 
-Use Python's standard ``doctest`` module to check stand-alone doctest file:
+使用 Python 标准库中的 ``doctest`` 模块检查独立的 doctest 文件：
 
     $ python3 -m doctest frenchdeck.doctest -v
 
-And to check doctests embedded in a module:
+检查嵌入在模块中的 doctest：
 
     $ python3 -m doctest vector2d.py -v
 
 ### Jupyter Notebook
 
-Install ``pytest`` and the ``nbval`` plugin:
+安装 ``pytest`` 及其 ``nbval`` 插件：
 
     $ pip install pytest nbval
 
-Run:
+运行：
 
     $ pytest --nbval
+
+---
+
+## 相关解释
+
+### 1. `python3 -m doctest frenchdeck.doctest -v` 是什么写法？
+
+这是在命令行中运行 Python 的一种方式：
+- `python3` 表示使用 Python 3 解释器。
+- `-m doctest` 表示用 doctest 这个标准库模块来运行。
+- `frenchdeck.doctest` 是要检查的文件名。
+- `-v` 表示 verbose（详细）模式，会输出更多信息。
+
+这条命令的意思是：用 doctest 模块检查 frenchdeck.doctest 文件中的测试，并详细输出结果。
+
+### 2. doctest 是什么模块？
+
+doctest 是 Python 标准库中的一个模块。它可以自动查找文档字符串（docstring）中的代码示例，并运行这些示例，检查它们的输出是否和文档中写的一致。这样可以保证文档中的代码示例是正确的。
+
+#### docstring 是什么？
+docstring（文档字符串）是写在 Python 函数、类、模块开头的字符串，用于描述该对象的用途和用法。通常用三引号括起来，紧跟在定义后面。例如：
+
+```python
+def add(a, b):
+    """返回 a 和 b 的和"""
+    return a + b
+```
+
+docstring 一般是开发者手写的，也可以通过一些文档生成工具自动生成模板，但内容通常需要人工补充和完善。
+
+### 3. doctest 如何进行检查？
+
+doctest 会扫描指定的文件或模块，查找形如 Python 交互式命令行（>>>）的代码块，然后执行这些代码，并把实际输出和文档中写的期望输出进行对比。如果一致，测试通过；否则会报告错误。
+
+### 4. "嵌入" 是什么？
+
+这里的“嵌入”指的是 doctest 代码示例直接写在 Python 源代码文件的文档字符串（docstring）里，而不是单独放在 .doctest 文件中。这样可以让文档和代码保持同步。
+
+### 5. `pytest --nbval` 又是什么？
+
+pytest 是一个流行的 Python 测试框架。nbval 是 pytest 的一个插件，可以让 pytest 检查 Jupyter Notebook（.ipynb 文件）中的代码单元格。
+
+`pytest --nbval` 这条命令会自动运行当前目录下所有的 Jupyter Notebook 文件，检查每个代码单元格的输出是否和 notebook 文件中保存的输出一致。如果不一致，就会报告错误。这有助于保证 notebook 文档的可重复性和正确性。
diff --git a/01-data-model/data-model.ipynb b/01-data-model/data-model.ipynb
index 5b30397..83d38db 100644
--- a/01-data-model/data-model.ipynb
+++ b/01-data-model/data-model.ipynb
@@ -19,6 +19,38 @@
     "## A Pythonic Card Deck"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### 相关问题讲解\n",
+    "\n",
+    "1. **collections 是什么？**\n",
+    "\n",
+    "   collections 是 Python 标准库中的一个模块，提供了许多有用的集合类，比如 namedtuple、deque、Counter、OrderedDict 等。这里用到的 namedtuple 可以用来创建类似元组的对象，并且可以通过属性名访问元素。\n",
+    "\n",
+    "2. **[str(n) for n in range(2, 11)] + list('JQKA') 中 [] 是列表吗？ 列表可以相加？**\n",
+    "\n",
+    "   - `[]` 是列表的定义方式，`[str(n) for n in range(2, 11)]` 是列表推导式，生成字符串 '2' 到 '10' 的列表。\n",
+    "   - `list('JQKA')` 会把字符串 'JQKA' 拆成 ['J', 'Q', 'K', 'A']。\n",
+    "   - 两个列表可以用 `+` 号相加，结果是拼接成一个新列表。\n",
+    "\n",
+    "3. **ranks、suits 是 FrenchDeck 这个类的属性吗？**\n",
+    "\n",
+    "   是的，`ranks` 和 `suits` 都是 FrenchDeck 类的类属性（class attribute），它们属于类本身，而不是某个实例。"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### 补充说明\n",
+    "\n",
+    "- `_cards` 不是类属性，而是 FrenchDeck 实例的属性（实例属性），它在 `__init__` 方法中通过 `self._cards = ...` 定义，每个实例都有自己的 `_cards`。\n",
+    "- `ranks` 和 `suits` 是在类体内直接定义的，属于 FrenchDeck 类本身（类属性），所有实例共享。\n",
+    "- 实例对象也可以通过 `self.ranks` 和 `self.suits` 访问类属性（如果实例没有同名属性时会自动查找类属性）。"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -28,7 +60,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 3,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -38,7 +70,7 @@
     "\n",
     "class FrenchDeck:\n",
     "    ranks = [str(n) for n in range(2, 11)] + list('JQKA')\n",
-    "    suits = 'spades diamonds clubs hearts'.split()\n",
+    "    suits = '♠️ ♥️ ♣️ ♦️'.split()\n",
     "\n",
     "    def __init__(self):\n",
     "        self._cards = [Card(rank, suit) for suit in self.suits for rank in self.ranks]\n",
@@ -52,28 +84,28 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 5,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "Card(rank='7', suit='diamonds')"
+       "Card(rank='7', suit='♣️')"
       ]
      },
-     "execution_count": 2,
+     "execution_count": 5,
      "metadata": {},
      "output_type": "execute_result"
     }
    ],
    "source": [
-    "beer_card = Card('7', 'diamonds')\n",
+    "beer_card = Card('7', '♣️')\n",
     "beer_card"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 8,
    "metadata": {},
    "outputs": [
     {
@@ -82,7 +114,7 @@
        "52"
       ]
      },
-     "execution_count": 3,
+     "execution_count": 8,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -94,16 +126,56 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 12,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "Card(rank='2', suit='spades')"
+       "['2', '3', '4', '5', '6', '7', '8', '9', '10', 'J', 'Q', 'K', 'A']"
       ]
      },
-     "execution_count": 4,
+     "execution_count": 12,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "deck.ranks"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "['♠️', '♥️', '♣️', '♦️']"
+      ]
+     },
+     "execution_count": 13,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "deck.suits"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "Card(rank='2', suit='♠️')"
+      ]
+     },
+     "execution_count": 9,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -114,16 +186,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 10,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "Card(rank='A', suit='hearts')"
+       "Card(rank='A', suit='♦️')"
       ]
      },
-     "execution_count": 5,
+     "execution_count": 10,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -134,16 +206,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 18,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "Card(rank='6', suit='diamonds')"
+       "Card(rank='3', suit='♣️')"
       ]
      },
-     "execution_count": 6,
+     "execution_count": 18,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -157,18 +229,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 19,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "[Card(rank='2', suit='spades'),\n",
-       " Card(rank='3', suit='spades'),\n",
-       " Card(rank='4', suit='spades')]"
+       "[Card(rank='2', suit='♠️'),\n",
+       " Card(rank='3', suit='♠️'),\n",
+       " Card(rank='4', suit='♠️')]"
       ]
      },
-     "execution_count": 7,
+     "execution_count": 19,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -179,19 +251,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 8,
+   "execution_count": 20,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "[Card(rank='A', suit='spades'),\n",
-       " Card(rank='A', suit='diamonds'),\n",
-       " Card(rank='A', suit='clubs'),\n",
-       " Card(rank='A', suit='hearts')]"
+       "[Card(rank='A', suit='♠️'),\n",
+       " Card(rank='A', suit='♥️'),\n",
+       " Card(rank='A', suit='♣️'),\n",
+       " Card(rank='A', suit='♦️')]"
       ]
      },
-     "execution_count": 8,
+     "execution_count": 20,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -202,65 +274,65 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 21,
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "Card(rank='2', suit='spades')\n",
-      "Card(rank='3', suit='spades')\n",
-      "Card(rank='4', suit='spades')\n",
-      "Card(rank='5', suit='spades')\n",
-      "Card(rank='6', suit='spades')\n",
-      "Card(rank='7', suit='spades')\n",
-      "Card(rank='8', suit='spades')\n",
-      "Card(rank='9', suit='spades')\n",
-      "Card(rank='10', suit='spades')\n",
-      "Card(rank='J', suit='spades')\n",
-      "Card(rank='Q', suit='spades')\n",
-      "Card(rank='K', suit='spades')\n",
-      "Card(rank='A', suit='spades')\n",
-      "Card(rank='2', suit='diamonds')\n",
-      "Card(rank='3', suit='diamonds')\n",
-      "Card(rank='4', suit='diamonds')\n",
-      "Card(rank='5', suit='diamonds')\n",
-      "Card(rank='6', suit='diamonds')\n",
-      "Card(rank='7', suit='diamonds')\n",
-      "Card(rank='8', suit='diamonds')\n",
-      "Card(rank='9', suit='diamonds')\n",
-      "Card(rank='10', suit='diamonds')\n",
-      "Card(rank='J', suit='diamonds')\n",
-      "Card(rank='Q', suit='diamonds')\n",
-      "Card(rank='K', suit='diamonds')\n",
-      "Card(rank='A', suit='diamonds')\n",
-      "Card(rank='2', suit='clubs')\n",
-      "Card(rank='3', suit='clubs')\n",
-      "Card(rank='4', suit='clubs')\n",
-      "Card(rank='5', suit='clubs')\n",
-      "Card(rank='6', suit='clubs')\n",
-      "Card(rank='7', suit='clubs')\n",
-      "Card(rank='8', suit='clubs')\n",
-      "Card(rank='9', suit='clubs')\n",
-      "Card(rank='10', suit='clubs')\n",
-      "Card(rank='J', suit='clubs')\n",
-      "Card(rank='Q', suit='clubs')\n",
-      "Card(rank='K', suit='clubs')\n",
-      "Card(rank='A', suit='clubs')\n",
-      "Card(rank='2', suit='hearts')\n",
-      "Card(rank='3', suit='hearts')\n",
-      "Card(rank='4', suit='hearts')\n",
-      "Card(rank='5', suit='hearts')\n",
-      "Card(rank='6', suit='hearts')\n",
-      "Card(rank='7', suit='hearts')\n",
-      "Card(rank='8', suit='hearts')\n",
-      "Card(rank='9', suit='hearts')\n",
-      "Card(rank='10', suit='hearts')\n",
-      "Card(rank='J', suit='hearts')\n",
-      "Card(rank='Q', suit='hearts')\n",
-      "Card(rank='K', suit='hearts')\n",
-      "Card(rank='A', suit='hearts')\n"
+      "Card(rank='2', suit='♠️')\n",
+      "Card(rank='3', suit='♠️')\n",
+      "Card(rank='4', suit='♠️')\n",
+      "Card(rank='5', suit='♠️')\n",
+      "Card(rank='6', suit='♠️')\n",
+      "Card(rank='7', suit='♠️')\n",
+      "Card(rank='8', suit='♠️')\n",
+      "Card(rank='9', suit='♠️')\n",
+      "Card(rank='10', suit='♠️')\n",
+      "Card(rank='J', suit='♠️')\n",
+      "Card(rank='Q', suit='♠️')\n",
+      "Card(rank='K', suit='♠️')\n",
+      "Card(rank='A', suit='♠️')\n",
+      "Card(rank='2', suit='♥️')\n",
+      "Card(rank='3', suit='♥️')\n",
+      "Card(rank='4', suit='♥️')\n",
+      "Card(rank='5', suit='♥️')\n",
+      "Card(rank='6', suit='♥️')\n",
+      "Card(rank='7', suit='♥️')\n",
+      "Card(rank='8', suit='♥️')\n",
+      "Card(rank='9', suit='♥️')\n",
+      "Card(rank='10', suit='♥️')\n",
+      "Card(rank='J', suit='♥️')\n",
+      "Card(rank='Q', suit='♥️')\n",
+      "Card(rank='K', suit='♥️')\n",
+      "Card(rank='A', suit='♥️')\n",
+      "Card(rank='2', suit='♣️')\n",
+      "Card(rank='3', suit='♣️')\n",
+      "Card(rank='4', suit='♣️')\n",
+      "Card(rank='5', suit='♣️')\n",
+      "Card(rank='6', suit='♣️')\n",
+      "Card(rank='7', suit='♣️')\n",
+      "Card(rank='8', suit='♣️')\n",
+      "Card(rank='9', suit='♣️')\n",
+      "Card(rank='10', suit='♣️')\n",
+      "Card(rank='J', suit='♣️')\n",
+      "Card(rank='Q', suit='♣️')\n",
+      "Card(rank='K', suit='♣️')\n",
+      "Card(rank='A', suit='♣️')\n",
+      "Card(rank='2', suit='♦️')\n",
+      "Card(rank='3', suit='♦️')\n",
+      "Card(rank='4', suit='♦️')\n",
+      "Card(rank='5', suit='♦️')\n",
+      "Card(rank='6', suit='♦️')\n",
+      "Card(rank='7', suit='♦️')\n",
+      "Card(rank='8', suit='♦️')\n",
+      "Card(rank='9', suit='♦️')\n",
+      "Card(rank='10', suit='♦️')\n",
+      "Card(rank='J', suit='♦️')\n",
+      "Card(rank='Q', suit='♦️')\n",
+      "Card(rank='K', suit='♦️')\n",
+      "Card(rank='A', suit='♦️')\n"
      ]
     }
    ],
@@ -271,65 +343,65 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 10,
+   "execution_count": 22,
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "Card(rank='A', suit='hearts')\n",
-      "Card(rank='K', suit='hearts')\n",
-      "Card(rank='Q', suit='hearts')\n",
-      "Card(rank='J', suit='hearts')\n",
-      "Card(rank='10', suit='hearts')\n",
-      "Card(rank='9', suit='hearts')\n",
-      "Card(rank='8', suit='hearts')\n",
-      "Card(rank='7', suit='hearts')\n",
-      "Card(rank='6', suit='hearts')\n",
-      "Card(rank='5', suit='hearts')\n",
-      "Card(rank='4', suit='hearts')\n",
-      "Card(rank='3', suit='hearts')\n",
-      "Card(rank='2', suit='hearts')\n",
-      "Card(rank='A', suit='clubs')\n",
-      "Card(rank='K', suit='clubs')\n",
-      "Card(rank='Q', suit='clubs')\n",
-      "Card(rank='J', suit='clubs')\n",
-      "Card(rank='10', suit='clubs')\n",
-      "Card(rank='9', suit='clubs')\n",
-      "Card(rank='8', suit='clubs')\n",
-      "Card(rank='7', suit='clubs')\n",
-      "Card(rank='6', suit='clubs')\n",
-      "Card(rank='5', suit='clubs')\n",
-      "Card(rank='4', suit='clubs')\n",
-      "Card(rank='3', suit='clubs')\n",
-      "Card(rank='2', suit='clubs')\n",
-      "Card(rank='A', suit='diamonds')\n",
-      "Card(rank='K', suit='diamonds')\n",
-      "Card(rank='Q', suit='diamonds')\n",
-      "Card(rank='J', suit='diamonds')\n",
-      "Card(rank='10', suit='diamonds')\n",
-      "Card(rank='9', suit='diamonds')\n",
-      "Card(rank='8', suit='diamonds')\n",
-      "Card(rank='7', suit='diamonds')\n",
-      "Card(rank='6', suit='diamonds')\n",
-      "Card(rank='5', suit='diamonds')\n",
-      "Card(rank='4', suit='diamonds')\n",
-      "Card(rank='3', suit='diamonds')\n",
-      "Card(rank='2', suit='diamonds')\n",
-      "Card(rank='A', suit='spades')\n",
-      "Card(rank='K', suit='spades')\n",
-      "Card(rank='Q', suit='spades')\n",
-      "Card(rank='J', suit='spades')\n",
-      "Card(rank='10', suit='spades')\n",
-      "Card(rank='9', suit='spades')\n",
-      "Card(rank='8', suit='spades')\n",
-      "Card(rank='7', suit='spades')\n",
-      "Card(rank='6', suit='spades')\n",
-      "Card(rank='5', suit='spades')\n",
-      "Card(rank='4', suit='spades')\n",
-      "Card(rank='3', suit='spades')\n",
-      "Card(rank='2', suit='spades')\n"
+      "Card(rank='A', suit='♦️')\n",
+      "Card(rank='K', suit='♦️')\n",
+      "Card(rank='Q', suit='♦️')\n",
+      "Card(rank='J', suit='♦️')\n",
+      "Card(rank='10', suit='♦️')\n",
+      "Card(rank='9', suit='♦️')\n",
+      "Card(rank='8', suit='♦️')\n",
+      "Card(rank='7', suit='♦️')\n",
+      "Card(rank='6', suit='♦️')\n",
+      "Card(rank='5', suit='♦️')\n",
+      "Card(rank='4', suit='♦️')\n",
+      "Card(rank='3', suit='♦️')\n",
+      "Card(rank='2', suit='♦️')\n",
+      "Card(rank='A', suit='♣️')\n",
+      "Card(rank='K', suit='♣️')\n",
+      "Card(rank='Q', suit='♣️')\n",
+      "Card(rank='J', suit='♣️')\n",
+      "Card(rank='10', suit='♣️')\n",
+      "Card(rank='9', suit='♣️')\n",
+      "Card(rank='8', suit='♣️')\n",
+      "Card(rank='7', suit='♣️')\n",
+      "Card(rank='6', suit='♣️')\n",
+      "Card(rank='5', suit='♣️')\n",
+      "Card(rank='4', suit='♣️')\n",
+      "Card(rank='3', suit='♣️')\n",
+      "Card(rank='2', suit='♣️')\n",
+      "Card(rank='A', suit='♥️')\n",
+      "Card(rank='K', suit='♥️')\n",
+      "Card(rank='Q', suit='♥️')\n",
+      "Card(rank='J', suit='♥️')\n",
+      "Card(rank='10', suit='♥️')\n",
+      "Card(rank='9', suit='♥️')\n",
+      "Card(rank='8', suit='♥️')\n",
+      "Card(rank='7', suit='♥️')\n",
+      "Card(rank='6', suit='♥️')\n",
+      "Card(rank='5', suit='♥️')\n",
+      "Card(rank='4', suit='♥️')\n",
+      "Card(rank='3', suit='♥️')\n",
+      "Card(rank='2', suit='♥️')\n",
+      "Card(rank='A', suit='♠️')\n",
+      "Card(rank='K', suit='♠️')\n",
+      "Card(rank='Q', suit='♠️')\n",
+      "Card(rank='J', suit='♠️')\n",
+      "Card(rank='10', suit='♠️')\n",
+      "Card(rank='9', suit='♠️')\n",
+      "Card(rank='8', suit='♠️')\n",
+      "Card(rank='7', suit='♠️')\n",
+      "Card(rank='6', suit='♠️')\n",
+      "Card(rank='5', suit='♠️')\n",
+      "Card(rank='4', suit='♠️')\n",
+      "Card(rank='3', suit='♠️')\n",
+      "Card(rank='2', suit='♠️')\n"
      ]
     }
    ],
@@ -340,7 +412,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": 24,
    "metadata": {},
    "outputs": [
     {
@@ -349,18 +421,18 @@
        "True"
       ]
      },
-     "execution_count": 11,
+     "execution_count": 24,
      "metadata": {},
      "output_type": "execute_result"
     }
    ],
    "source": [
-    "Card('Q', 'hearts') in deck"
+    "Card('Q', '♠️') in deck"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 12,
+   "execution_count": 25,
    "metadata": {},
    "outputs": [
     {
@@ -369,7 +441,7 @@
        "False"
       ]
      },
-     "execution_count": 12,
+     "execution_count": 25,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -380,70 +452,71 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 13,
+   "execution_count": 32,
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "Card(rank='2', suit='clubs')\n",
-      "Card(rank='2', suit='diamonds')\n",
-      "Card(rank='2', suit='hearts')\n",
-      "Card(rank='2', suit='spades')\n",
-      "Card(rank='3', suit='clubs')\n",
-      "Card(rank='3', suit='diamonds')\n",
-      "Card(rank='3', suit='hearts')\n",
-      "Card(rank='3', suit='spades')\n",
-      "Card(rank='4', suit='clubs')\n",
-      "Card(rank='4', suit='diamonds')\n",
-      "Card(rank='4', suit='hearts')\n",
-      "Card(rank='4', suit='spades')\n",
-      "Card(rank='5', suit='clubs')\n",
-      "Card(rank='5', suit='diamonds')\n",
-      "Card(rank='5', suit='hearts')\n",
-      "Card(rank='5', suit='spades')\n",
-      "Card(rank='6', suit='clubs')\n",
-      "Card(rank='6', suit='diamonds')\n",
-      "Card(rank='6', suit='hearts')\n",
-      "Card(rank='6', suit='spades')\n",
-      "Card(rank='7', suit='clubs')\n",
-      "Card(rank='7', suit='diamonds')\n",
-      "Card(rank='7', suit='hearts')\n",
-      "Card(rank='7', suit='spades')\n",
-      "Card(rank='8', suit='clubs')\n",
-      "Card(rank='8', suit='diamonds')\n",
-      "Card(rank='8', suit='hearts')\n",
-      "Card(rank='8', suit='spades')\n",
-      "Card(rank='9', suit='clubs')\n",
-      "Card(rank='9', suit='diamonds')\n",
-      "Card(rank='9', suit='hearts')\n",
-      "Card(rank='9', suit='spades')\n",
-      "Card(rank='10', suit='clubs')\n",
-      "Card(rank='10', suit='diamonds')\n",
-      "Card(rank='10', suit='hearts')\n",
-      "Card(rank='10', suit='spades')\n",
-      "Card(rank='J', suit='clubs')\n",
-      "Card(rank='J', suit='diamonds')\n",
-      "Card(rank='J', suit='hearts')\n",
-      "Card(rank='J', suit='spades')\n",
-      "Card(rank='Q', suit='clubs')\n",
-      "Card(rank='Q', suit='diamonds')\n",
-      "Card(rank='Q', suit='hearts')\n",
-      "Card(rank='Q', suit='spades')\n",
-      "Card(rank='K', suit='clubs')\n",
-      "Card(rank='K', suit='diamonds')\n",
-      "Card(rank='K', suit='hearts')\n",
-      "Card(rank='K', suit='spades')\n",
-      "Card(rank='A', suit='clubs')\n",
-      "Card(rank='A', suit='diamonds')\n",
-      "Card(rank='A', suit='hearts')\n",
-      "Card(rank='A', suit='spades')\n"
+      "Card(rank='2', suit='♦️')\n",
+      "Card(rank='2', suit='♣️')\n",
+      "Card(rank='2', suit='♥️')\n",
+      "Card(rank='2', suit='♠️')\n",
+      "Card(rank='3', suit='♦️')\n",
+      "Card(rank='3', suit='♣️')\n",
+      "Card(rank='3', suit='♥️')\n",
+      "Card(rank='3', suit='♠️')\n",
+      "Card(rank='4', suit='♦️')\n",
+      "Card(rank='4', suit='♣️')\n",
+      "Card(rank='4', suit='♥️')\n",
+      "Card(rank='4', suit='♠️')\n",
+      "Card(rank='5', suit='♦️')\n",
+      "Card(rank='5', suit='♣️')\n",
+      "Card(rank='5', suit='♥️')\n",
+      "Card(rank='5', suit='♠️')\n",
+      "Card(rank='6', suit='♦️')\n",
+      "Card(rank='6', suit='♣️')\n",
+      "Card(rank='6', suit='♥️')\n",
+      "Card(rank='6', suit='♠️')\n",
+      "Card(rank='7', suit='♦️')\n",
+      "Card(rank='7', suit='♣️')\n",
+      "Card(rank='7', suit='♥️')\n",
+      "Card(rank='7', suit='♠️')\n",
+      "Card(rank='8', suit='♦️')\n",
+      "Card(rank='8', suit='♣️')\n",
+      "Card(rank='8', suit='♥️')\n",
+      "Card(rank='8', suit='♠️')\n",
+      "Card(rank='9', suit='♦️')\n",
+      "Card(rank='9', suit='♣️')\n",
+      "Card(rank='9', suit='♥️')\n",
+      "Card(rank='9', suit='♠️')\n",
+      "Card(rank='10', suit='♦️')\n",
+      "Card(rank='10', suit='♣️')\n",
+      "Card(rank='10', suit='♥️')\n",
+      "Card(rank='10', suit='♠️')\n",
+      "Card(rank='J', suit='♦️')\n",
+      "Card(rank='J', suit='♣️')\n",
+      "Card(rank='J', suit='♥️')\n",
+      "Card(rank='J', suit='♠️')\n",
+      "Card(rank='Q', suit='♦️')\n",
+      "Card(rank='Q', suit='♣️')\n",
+      "Card(rank='Q', suit='♥️')\n",
+      "Card(rank='Q', suit='♠️')\n",
+      "Card(rank='K', suit='♦️')\n",
+      "Card(rank='K', suit='♣️')\n",
+      "Card(rank='K', suit='♥️')\n",
+      "Card(rank='K', suit='♠️')\n",
+      "Card(rank='A', suit='♦️')\n",
+      "Card(rank='A', suit='♣️')\n",
+      "Card(rank='A', suit='♥️')\n",
+      "Card(rank='A', suit='♠️')\n"
      ]
     }
    ],
    "source": [
-    "suit_values = dict(spades=3, hearts=2, diamonds=1, clubs=0)\n",
+    "# suit_values = dict(spades=3, hearts=2, diamonds=1, clubs=0)\n",
+    "suit_values = {'♠️': 3, '♥️': 2, '♣️': 1, '♦️': 0}\n",
     "\n",
     "def spades_high(card):\n",
     "    rank_value = FrenchDeck.ranks.index(card.rank)\n",
@@ -467,9 +540,23 @@
     "#### Example 1-2. A simple two-dimensional vector class"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### 相关讲解\n",
+    "\n",
+    "- `!r` 是 Python 格式化字符串（f-string）中的格式说明符，表示用 `repr()` 的方式显示变量的值。例如：`f\"{value!r}\"` 等价于 `f\"{repr(value)}\"`。\n",
+    "- `__repr__` 方法用于定义对象的“官方”字符串表示，通常用于调试和开发，要求尽量准确、清晰地反映对象内容。\n",
+    "- f-string 默认用 `str()` 格式化变量，只有加上 `!r` 才会用 `repr()` 格式化。\n",
+    "- 例如：\n",
+    "  - `f\"{value}\"` 等价于 `str(value)`\n",
+    "  - `f\"{value!r}\"` 等价于 `repr(value)`"
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -501,7 +588,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 15,
+   "execution_count": 45,
    "metadata": {},
    "outputs": [
     {
@@ -510,7 +597,7 @@
        "Vector(4, 5)"
       ]
      },
-     "execution_count": 15,
+     "execution_count": 45,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -523,7 +610,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 16,
+   "execution_count": 36,
    "metadata": {},
    "outputs": [
     {
@@ -532,7 +619,7 @@
        "5.0"
       ]
      },
-     "execution_count": 16,
+     "execution_count": 36,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -544,7 +631,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 17,
+   "execution_count": 37,
    "metadata": {},
    "outputs": [
     {
@@ -553,7 +640,7 @@
        "Vector(9, 12)"
       ]
      },
-     "execution_count": 17,
+     "execution_count": 37,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -564,7 +651,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 18,
+   "execution_count": 38,
    "metadata": {},
    "outputs": [
     {
@@ -573,7 +660,7 @@
        "15.0"
       ]
      },
-     "execution_count": 18,
+     "execution_count": 38,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -581,11 +668,31 @@
    "source": [
     "abs(v * 3)"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 39,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "True"
+      ]
+     },
+     "execution_count": 39,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "bool(v)"
+   ]
   }
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": ".venv",
    "language": "python",
    "name": "python3"
   },
@@ -599,7 +706,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.0"
+   "version": "3.12.3"
   }
  },
  "nbformat": 4,
diff --git a/02-array-seq/array-seq.ipynb b/02-array-seq/array-seq.ipynb
index afdbf6b..3a60197 100644
--- a/02-array-seq/array-seq.ipynb
+++ b/02-array-seq/array-seq.ipynb
@@ -39,20 +39,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 2,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "[36, 162, 163, 165, 8364, 164]"
+      "text/plain": [
+       "[65, 97, 36, 162, 163, 165, 8364, 164]"
+      ]
      },
-     "execution_count": 1,
+     "execution_count": 2,
      "metadata": {},
      "output_type": "execute_result"
     }
    ],
    "source": [
-    "symbols = '$¢£¥€¤'\n",
+    "symbols = 'Aa$¢£¥€¤'\n",
     "codes = []\n",
     "\n",
     "for symbol in symbols:\n",
@@ -70,20 +72,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 1,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "[36, 162, 163, 165, 8364, 164]"
+      "text/plain": [
+       "[36, 162, 163, 165, 8364, 164, 65, 97]"
+      ]
      },
-     "execution_count": 2,
+     "execution_count": 1,
      "metadata": {},
      "output_type": "execute_result"
     }
    ],
    "source": [
-    "symbols = '$¢£¥€¤'\n",
+    "symbols = '$¢£¥€¤Aa'\n",
     "\n",
     "codes = [ord(symbol) for symbol in symbols]\n",
     "\n",
@@ -99,14 +103,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 2,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "'ABC'"
+      "text/plain": [
+       "'ABC'"
+      ]
      },
-     "execution_count": 3,
+     "execution_count": 2,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -119,14 +125,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 3,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "[65, 66, 67]"
+      "text/plain": [
+       "[65, 66, 67]"
+      ]
      },
-     "execution_count": 4,
+     "execution_count": 3,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -137,13 +145,21 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "67"
+      "text/plain": [
+       "67"
+      ]
      },
-     "execution_count": 5,
+     "execution_count": 4,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -151,13 +167,7 @@
    "source": [
     "codes = [last := ord(c) for c in x]\n",
     "last"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%%\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
@@ -168,14 +178,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 5,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "[162, 163, 165, 8364, 164]"
+      "text/plain": [
+       "[162, 163, 165, 8364, 164]"
+      ]
      },
-     "execution_count": 6,
+     "execution_count": 5,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -188,14 +200,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 6,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "[162, 163, 165, 8364, 164]"
+      "text/plain": [
+       "[162, 163, 165, 8364, 164]"
+      ]
      },
-     "execution_count": 7,
+     "execution_count": 6,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -214,14 +228,21 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 8,
+   "execution_count": 10,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "[('black', 'S'),\n ('black', 'M'),\n ('black', 'L'),\n ('white', 'S'),\n ('white', 'M'),\n ('white', 'L')]"
+      "text/plain": [
+       "[('black', 'S'),\n",
+       " ('black', 'M'),\n",
+       " ('black', 'L'),\n",
+       " ('white', 'S'),\n",
+       " ('white', 'M'),\n",
+       " ('white', 'L')]"
+      ]
      },
-     "execution_count": 8,
+     "execution_count": 10,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -235,7 +256,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 11,
    "metadata": {},
    "outputs": [
     {
@@ -259,20 +280,27 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 10,
+   "execution_count": 18,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "[('black', 'S'),\n ('black', 'M'),\n ('black', 'L'),\n ('white', 'S'),\n ('white', 'M'),\n ('white', 'L')]"
+      "text/plain": [
+       "[('black', 'S'),\n",
+       " ('white', 'S'),\n",
+       " ('black', 'M'),\n",
+       " ('white', 'M'),\n",
+       " ('black', 'L'),\n",
+       " ('white', 'L')]"
+      ]
      },
-     "execution_count": 10,
+     "execution_count": 18,
      "metadata": {},
      "output_type": "execute_result"
     }
    ],
    "source": [
-    "shirts = [(color, size) for size in sizes\n",
+    "tshirts = [(color, size) for size in sizes\n",
     "          for color in colors]\n",
     "tshirts"
    ]
@@ -291,7 +319,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "(36, 162, 163, 165, 8364, 164)"
+      "text/plain": [
+       "(36, 162, 163, 165, 8364, 164)"
+      ]
      },
      "execution_count": 11,
      "metadata": {},
@@ -305,14 +335,36 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 12,
+   "execution_count": 21,
    "metadata": {},
    "outputs": [
     {
      "data": {
-      "text/plain": "array('I', [36, 162, 163, 165, 8364, 164])"
+      "text/plain": [
+       "[36, 162, 163, 165, 8364, 164]"
+      ]
      },
-     "execution_count": 12,
+     "execution_count": 21,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "list(ord(symbol) for symbol in symbols)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "array('I', [36, 162, 163, 165, 8364, 164])"
+      ]
+     },
+     "execution_count": 22,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -332,7 +384,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 13,
+   "execution_count": 27,
    "metadata": {},
    "outputs": [
     {
@@ -352,38 +404,45 @@
     "colors = ['black', 'white']\n",
     "sizes = ['S', 'M', 'L']\n",
     "\n",
-    "for tshirt in ('%s %s' % (c, s) for c in colors for s in sizes):\n",
+    "# for tshirt in ('%s %s' % (c, s) for c in colors for s in sizes):\n",
+    "#     print(tshirt)\n",
+    "for tshirt in (f'{c} {s}' for c in colors for s in sizes):\n",
     "    print(tshirt)"
    ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "## Tuples Are Not Just Immutable Lists"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
    },
-   "execution_count": 73
+   "source": [
+    "## Tuples Are Not Just Immutable Lists"
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "#### Example 2-7. Tuples used as records"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "#### Example 2-7. Tuples used as records"
+   ]
   },
   {
    "cell_type": "code",
    "execution_count": 14,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [
     {
      "name": "stdout",
@@ -402,17 +461,17 @@
     "\n",
     "for passport in sorted(traveler_ids):\n",
     "    print('%s/%s' % passport)"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 15,
+   },
    "outputs": [
     {
      "name": "stdout",
@@ -427,33 +486,35 @@
    "source": [
     "for country, _ in traveler_ids:\n",
     "    print(country)"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%%\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "### Tuples as Immutable Lists"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "### Tuples as Immutable Lists"
+   ]
   },
   {
    "cell_type": "code",
    "execution_count": 16,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "True"
+      "text/plain": [
+       "True"
+      ]
      },
      "execution_count": 16,
      "metadata": {},
@@ -464,21 +525,23 @@
     "a = (10, 'alpha', [1, 2])\n",
     "b = (10, 'alpha', [1, 2])\n",
     "a == b"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 17,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "False"
+      "text/plain": [
+       "False"
+      ]
      },
      "execution_count": 17,
      "metadata": {},
@@ -488,21 +551,23 @@
    "source": [
     "b[-1].append(99)\n",
     "a == b"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 18,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(10, 'alpha', [1, 2, 99])"
+      "text/plain": [
+       "(10, 'alpha', [1, 2, 99])"
+      ]
      },
      "execution_count": 18,
      "metadata": {},
@@ -511,21 +576,23 @@
    ],
    "source": [
     "b"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 19,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "True"
+      "text/plain": [
+       "True"
+      ]
      },
      "execution_count": 19,
      "metadata": {},
@@ -544,21 +611,23 @@
     "tf = (10, 'alpha', (1, 2))  # Contains no mutable items\n",
     "tm = (10, 'alpha', [1, 2])  # Contains a mutable item (list)\n",
     "fixed(tf)"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 20,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "False"
+      "text/plain": [
+       "False"
+      ]
      },
      "execution_count": 20,
      "metadata": {},
@@ -567,33 +636,35 @@
    ],
    "source": [
     "fixed(tm)"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%%\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "## Unpacking sequences and iterables"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "## Unpacking sequences and iterables"
+   ]
   },
   {
    "cell_type": "code",
    "execution_count": 21,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "33.9425"
+      "text/plain": [
+       "33.9425"
+      ]
      },
      "execution_count": 21,
      "metadata": {},
@@ -604,21 +675,23 @@
     "lax_coordinates = (33.9425, -118.408056)\n",
     "latitude, longitude = lax_coordinates  # unpacking\n",
     "latitude"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 22,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "-118.408056"
+      "text/plain": [
+       "-118.408056"
+      ]
      },
      "execution_count": 22,
      "metadata": {},
@@ -627,21 +700,23 @@
    ],
    "source": [
     "longitude"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 23,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 23,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(2, 4)"
+      "text/plain": [
+       "(2, 4)"
+      ]
      },
      "execution_count": 23,
      "metadata": {},
@@ -650,21 +725,23 @@
    ],
    "source": [
     "divmod(20, 8)"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 24,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(2, 4)"
+      "text/plain": [
+       "(2, 4)"
+      ]
      },
      "execution_count": 24,
      "metadata": {},
@@ -674,21 +751,23 @@
    "source": [
     "t = (20, 8)\n",
     "divmod(*t)"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 25,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(2, 4)"
+      "text/plain": [
+       "(2, 4)"
+      ]
      },
      "execution_count": 25,
      "metadata": {},
@@ -698,21 +777,23 @@
    "source": [
     "quotient, remainder = divmod(*t)\n",
     "quotient, remainder"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 26,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "'id_rsa.pub'"
+      "text/plain": [
+       "'id_rsa.pub'"
+      ]
      },
      "execution_count": 26,
      "metadata": {},
@@ -724,33 +805,35 @@
     "\n",
     "_, filename = os.path.split('/home/luciano/.ssh/id_rsa.pub')\n",
     "filename"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%%\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "### Using * to grab excess items"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "### Using * to grab excess items"
+   ]
   },
   {
    "cell_type": "code",
    "execution_count": 27,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(0, 1, [2, 3, 4])"
+      "text/plain": [
+       "(0, 1, [2, 3, 4])"
+      ]
      },
      "execution_count": 27,
      "metadata": {},
@@ -760,21 +843,23 @@
    "source": [
     "a, b, *rest = range(5)\n",
     "a, b, rest"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 28,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(0, 1, [2])"
+      "text/plain": [
+       "(0, 1, [2])"
+      ]
      },
      "execution_count": 28,
      "metadata": {},
@@ -784,21 +869,23 @@
    "source": [
     "a, b, *rest = range(3)\n",
     "a, b, rest"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 29,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 29,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(0, 1, [])"
+      "text/plain": [
+       "(0, 1, [])"
+      ]
      },
      "execution_count": 29,
      "metadata": {},
@@ -808,21 +895,23 @@
    "source": [
     "a, b, *rest = range(2)\n",
     "a, b, rest"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 30,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(0, [1, 2], 3, 4)"
+      "text/plain": [
+       "(0, [1, 2], 3, 4)"
+      ]
      },
      "execution_count": 30,
      "metadata": {},
@@ -832,21 +921,23 @@
    "source": [
     "a, *body, c, d = range(5)\n",
     "a, body, c, d"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 31,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "([0, 1], 2, 3, 4)"
+      "text/plain": [
+       "([0, 1], 2, 3, 4)"
+      ]
      },
      "execution_count": 31,
      "metadata": {},
@@ -856,33 +947,35 @@
    "source": [
     "*head, b, c, d = range(5)\n",
     "head, b, c, d"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%%\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "### Unpacking with * in function calls and sequence literals"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "### Unpacking with * in function calls and sequence literals"
+   ]
   },
   {
    "cell_type": "code",
    "execution_count": 32,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(1, 2, 3, 4, (5, 6))"
+      "text/plain": [
+       "(1, 2, 3, 4, (5, 6))"
+      ]
      },
      "execution_count": 32,
      "metadata": {},
@@ -895,21 +988,23 @@
     "\n",
     "\n",
     "fun(*[1, 2], 3, *range(4, 7))"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 33,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 33,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "(0, 1, 2, 3, 4)"
+      "text/plain": [
+       "(0, 1, 2, 3, 4)"
+      ]
      },
      "execution_count": 33,
      "metadata": {},
@@ -918,21 +1013,23 @@
    ],
    "source": [
     "*range(4), 4"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 34,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 34,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, 1, 2, 3, 4]"
+      "text/plain": [
+       "[0, 1, 2, 3, 4]"
+      ]
      },
      "execution_count": 34,
      "metadata": {},
@@ -941,21 +1038,23 @@
    ],
    "source": [
     "[*range(4), 4]"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 35,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "{0, 1, 2, 3, 4, 5, 6, 7}"
+      "text/plain": [
+       "{0, 1, 2, 3, 4, 5, 6, 7}"
+      ]
      },
      "execution_count": 35,
      "metadata": {},
@@ -964,45 +1063,45 @@
    ],
    "source": [
     "{*range(4), 4, *(5, 6, 7)}"
-   ],
+   ]
+  },
+  {
+   "cell_type": "markdown",
    "metadata": {
     "collapsed": false,
     "pycharm": {
-     "name": "#%%\n"
+     "name": "#%% md\n"
     }
-   }
-  },
-  {
-   "cell_type": "markdown",
+   },
    "source": [
     "### Nested unpacking\n",
     "#### Example 2-8. Unpacking nested tuples to access the longitude\n",
     "\n",
     "[02-array-seq/metro_lat_lon.py](02-array-seq/metro_lat_lon.py)"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%% md\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "## Pattern Matching with Sequences\n",
-    "#### Example 2-9. Method from an imaginary Robot class"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "## Pattern Matching with Sequences\n",
+    "#### Example 2-9. Method from an imaginary Robot class"
+   ]
   },
   {
    "cell_type": "code",
    "execution_count": 36,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [],
    "source": [
     "# def handle_command(self, message):\n",
@@ -1017,30 +1116,30 @@
     "#             self.leds[ident].set_color(ident, red, green, blue)\n",
     "#         case _:\n",
     "#             raise InvalidCommand(message)"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%%\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "#### Example 2-10. Destructuring nested tuples—requires Python ≥ 3.10.\n",
-    "[02-array-seq/match_lat_lon.py](02-array-seq/match_lat_lon.py)"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "#### Example 2-10. Destructuring nested tuples—requires Python ≥ 3.10.\n",
+    "[02-array-seq/match_lat_lon.py](02-array-seq/match_lat_lon.py)"
+   ]
   },
   {
    "cell_type": "code",
    "execution_count": 37,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [
     {
      "name": "stdout",
@@ -1069,57 +1168,51 @@
     "            case [name, _, _, (lat, lon)] if lon <= 0:\n",
     "                print(f'{name:15} | {lat:9.4f} | {lon:9.4f}')\n",
     "main()"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%%\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": []
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "### Pattern Matching Sequences in an Interpreter\n",
-    "#### Example 2-11. Matching patterns without match/case.\n",
-    "[02-array-seq/lispy/py3.9/lis.py](02-array-seq/lispy/py3.9/lis.py)"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "### Pattern Matching Sequences in an Interpreter\n",
+    "#### Example 2-11. Matching patterns without match/case.\n",
+    "[02-array-seq/lispy/py3.9/lis.py](02-array-seq/lispy/py3.9/lis.py)"
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "#### Example 2-12. Pattern matching with match/case—requires Python ≥ 3.10.\n",
-    "[02-array-seq/lispy/py3.10/lis.py](02-array-seq/lispy/py3.10/lis.py)"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "#### Example 2-12. Pattern matching with match/case—requires Python ≥ 3.10.\n",
+    "[02-array-seq/lispy/py3.10/lis.py](02-array-seq/lispy/py3.10/lis.py)"
+   ]
   },
   {
    "cell_type": "markdown",
-   "source": [],
    "metadata": {
     "collapsed": false
-   }
+   },
+   "source": []
   },
   {
    "cell_type": "markdown",
@@ -1142,7 +1235,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[10, 20]"
+      "text/plain": [
+       "[10, 20]"
+      ]
      },
      "execution_count": 38,
      "metadata": {},
@@ -1162,7 +1257,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[30, 40, 50, 60]"
+      "text/plain": [
+       "[30, 40, 50, 60]"
+      ]
      },
      "execution_count": 39,
      "metadata": {},
@@ -1180,7 +1277,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[10, 20, 30]"
+      "text/plain": [
+       "[10, 20, 30]"
+      ]
      },
      "execution_count": 40,
      "metadata": {},
@@ -1198,7 +1297,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[40, 50, 60]"
+      "text/plain": [
+       "[40, 50, 60]"
+      ]
      },
      "execution_count": 41,
      "metadata": {},
@@ -1223,7 +1324,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "'bye'"
+      "text/plain": [
+       "'bye'"
+      ]
      },
      "execution_count": 42,
      "metadata": {},
@@ -1242,7 +1345,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "'elcycib'"
+      "text/plain": [
+       "'elcycib'"
+      ]
      },
      "execution_count": 43,
      "metadata": {},
@@ -1260,7 +1365,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "'eccb'"
+      "text/plain": [
+       "'eccb'"
+      ]
      },
      "execution_count": 44,
      "metadata": {},
@@ -1330,7 +1437,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
+      "text/plain": [
+       "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
+      ]
      },
      "execution_count": 46,
      "metadata": {},
@@ -1349,7 +1458,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, 1, 20, 30, 5, 6, 7, 8, 9]"
+      "text/plain": [
+       "[0, 1, 20, 30, 5, 6, 7, 8, 9]"
+      ]
      },
      "execution_count": 47,
      "metadata": {},
@@ -1368,7 +1479,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, 1, 20, 30, 5, 8, 9]"
+      "text/plain": [
+       "[0, 1, 20, 30, 5, 8, 9]"
+      ]
      },
      "execution_count": 48,
      "metadata": {},
@@ -1387,7 +1500,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, 1, 20, 11, 5, 22, 9]"
+      "text/plain": [
+       "[0, 1, 20, 11, 5, 22, 9]"
+      ]
      },
      "execution_count": 49,
      "metadata": {},
@@ -1433,7 +1548,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, 1, 100, 22, 9]"
+      "text/plain": [
+       "[0, 1, 100, 22, 9]"
+      ]
      },
      "execution_count": 51,
      "metadata": {},
@@ -1459,7 +1576,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]"
+      "text/plain": [
+       "[1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3]"
+      ]
      },
      "execution_count": 52,
      "metadata": {},
@@ -1478,7 +1597,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "'abcdabcdabcdabcdabcd'"
+      "text/plain": [
+       "'abcdabcdabcdabcdabcd'"
+      ]
      },
      "execution_count": 53,
      "metadata": {},
@@ -1510,7 +1631,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]"
+      "text/plain": [
+       "[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]"
+      ]
      },
      "execution_count": 54,
      "metadata": {},
@@ -1529,7 +1652,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[['_', '_', '_'], ['_', '_', 'X'], ['_', '_', '_']]"
+      "text/plain": [
+       "[['_', '_', '_'], ['_', '_', 'X'], ['_', '_', '_']]"
+      ]
      },
      "execution_count": 55,
      "metadata": {},
@@ -1555,7 +1680,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]"
+      "text/plain": [
+       "[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]"
+      ]
      },
      "execution_count": 56,
      "metadata": {},
@@ -1574,7 +1701,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[['_', '_', 'O'], ['_', '_', 'O'], ['_', '_', 'O']]"
+      "text/plain": [
+       "[['_', '_', 'O'], ['_', '_', 'O'], ['_', '_', 'O']]"
+      ]
      },
      "execution_count": 57,
      "metadata": {},
@@ -1600,7 +1729,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]"
+      "text/plain": [
+       "[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]"
+      ]
      },
      "execution_count": 58,
      "metadata": {},
@@ -1622,7 +1753,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[['_', '_', '_'], ['_', '_', '_'], ['X', '_', '_']]"
+      "text/plain": [
+       "[['_', '_', '_'], ['_', '_', '_'], ['X', '_', '_']]"
+      ]
      },
      "execution_count": 59,
      "metadata": {},
@@ -1658,7 +1791,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "140694277263808"
+      "text/plain": [
+       "140694277263808"
+      ]
      },
      "execution_count": 61,
      "metadata": {},
@@ -1677,7 +1812,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[1, 2, 3, 1, 2, 3]"
+      "text/plain": [
+       "[1, 2, 3, 1, 2, 3]"
+      ]
      },
      "execution_count": 62,
      "metadata": {},
@@ -1696,7 +1833,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "True"
+      "text/plain": [
+       "True"
+      ]
      },
      "execution_count": 63,
      "metadata": {},
@@ -1724,7 +1863,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "140694329335488"
+      "text/plain": [
+       "140694329335488"
+      ]
      },
      "execution_count": 65,
      "metadata": {},
@@ -1743,7 +1884,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "False"
+      "text/plain": [
+       "False"
+      ]
      },
      "execution_count": 66,
      "metadata": {},
@@ -1786,15 +1929,15 @@
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "#### Example 2-17. The unexpected result: item t2 is changed and an exception is raised"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "#### Example 2-17. The unexpected result: item t2 is changed and an exception is raised"
+   ]
   },
   {
    "cell_type": "code",
@@ -1803,7 +1946,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "(1, 2, [30, 40, 50, 60])"
+      "text/plain": [
+       "(1, 2, [30, 40, 50, 60])"
+      ]
      },
      "execution_count": 68,
      "metadata": {},
@@ -1863,7 +2008,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "['apple', 'banana', 'grape', 'raspberry']"
+      "text/plain": [
+       "['apple', 'banana', 'grape', 'raspberry']"
+      ]
      },
      "execution_count": 70,
      "metadata": {},
@@ -1882,7 +2029,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "['grape', 'raspberry', 'apple', 'banana']"
+      "text/plain": [
+       "['grape', 'raspberry', 'apple', 'banana']"
+      ]
      },
      "execution_count": 71,
      "metadata": {},
@@ -1900,7 +2049,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "['raspberry', 'grape', 'banana', 'apple']"
+      "text/plain": [
+       "['raspberry', 'grape', 'banana', 'apple']"
+      ]
      },
      "execution_count": 72,
      "metadata": {},
@@ -1918,7 +2069,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "['grape', 'apple', 'banana', 'raspberry']"
+      "text/plain": [
+       "['grape', 'apple', 'banana', 'raspberry']"
+      ]
      },
      "execution_count": 73,
      "metadata": {},
@@ -1936,7 +2089,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "['raspberry', 'banana', 'grape', 'apple']"
+      "text/plain": [
+       "['raspberry', 'banana', 'grape', 'apple']"
+      ]
      },
      "execution_count": 74,
      "metadata": {},
@@ -1954,7 +2109,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "['grape', 'raspberry', 'apple', 'banana']"
+      "text/plain": [
+       "['grape', 'raspberry', 'apple', 'banana']"
+      ]
      },
      "execution_count": 75,
      "metadata": {},
@@ -1972,7 +2129,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "['apple', 'banana', 'grape', 'raspberry']"
+      "text/plain": [
+       "['apple', 'banana', 'grape', 'raspberry']"
+      ]
      },
      "execution_count": 76,
      "metadata": {},
@@ -2012,7 +2171,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "0.8190492979077034"
+      "text/plain": [
+       "0.8190492979077034"
+      ]
      },
      "execution_count": 77,
      "metadata": {},
@@ -2045,7 +2206,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "0.8190492979077034"
+      "text/plain": [
+       "0.8190492979077034"
+      ]
      },
      "execution_count": 79,
      "metadata": {},
@@ -2068,7 +2231,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "True"
+      "text/plain": [
+       "True"
+      ]
      },
      "execution_count": 80,
      "metadata": {},
@@ -2088,23 +2253,31 @@
   },
   {
    "cell_type": "markdown",
-   "source": [
-    "#### Example 2-20. Handling 6 bytes memory of as 1×6, 2×3, and 3×2 views"
-   ],
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%% md\n"
     }
-   }
+   },
+   "source": [
+    "#### Example 2-20. Handling 6 bytes memory of as 1×6, 2×3, and 3×2 views"
+   ]
   },
   {
    "cell_type": "code",
    "execution_count": 81,
+   "metadata": {
+    "collapsed": false,
+    "pycharm": {
+     "name": "#%%\n"
+    }
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, 1, 2, 3, 4, 5]"
+      "text/plain": [
+       "[0, 1, 2, 3, 4, 5]"
+      ]
      },
      "execution_count": 81,
      "metadata": {},
@@ -2115,21 +2288,23 @@
     "octets = array('B', range(6))\n",
     "m1 = memoryview(octets)\n",
     "m1.tolist()"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 82,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 82,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "[[0, 1, 2], [3, 4, 5]]"
+      "text/plain": [
+       "[[0, 1, 2], [3, 4, 5]]"
+      ]
      },
      "execution_count": 82,
      "metadata": {},
@@ -2139,21 +2314,23 @@
    "source": [
     "m2 = m1.cast('B', [2, 3])\n",
     "m2.tolist()"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 83,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 83,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "[[0, 1], [2, 3], [4, 5]]"
+      "text/plain": [
+       "[[0, 1], [2, 3], [4, 5]]"
+      ]
      },
      "execution_count": 83,
      "metadata": {},
@@ -2163,21 +2340,23 @@
    "source": [
     "m3 = m1.cast('B', [3, 2])\n",
     "m3.tolist()"
-   ],
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 84,
    "metadata": {
     "collapsed": false,
     "pycharm": {
      "name": "#%%\n"
     }
-   }
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 84,
+   },
    "outputs": [
     {
      "data": {
-      "text/plain": "array('B', [0, 1, 2, 33, 22, 5])"
+      "text/plain": [
+       "array('B', [0, 1, 2, 33, 22, 5])"
+      ]
      },
      "execution_count": 84,
      "metadata": {},
@@ -2188,13 +2367,7 @@
     "m2[1,1] = 22\n",
     "m3[1,1] = 33\n",
     "octets"
-   ],
-   "metadata": {
-    "collapsed": false,
-    "pycharm": {
-     "name": "#%%\n"
-    }
-   }
+   ]
   },
   {
    "cell_type": "markdown",
@@ -2210,7 +2383,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "5"
+      "text/plain": [
+       "5"
+      ]
      },
      "execution_count": 85,
      "metadata": {},
@@ -2230,7 +2405,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "-2"
+      "text/plain": [
+       "-2"
+      ]
      },
      "execution_count": 86,
      "metadata": {},
@@ -2248,7 +2425,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[254, 255, 255, 255, 0, 0, 1, 0, 2, 0]"
+      "text/plain": [
+       "[254, 255, 255, 255, 0, 0, 1, 0, 2, 0]"
+      ]
      },
      "execution_count": 87,
      "metadata": {},
@@ -2267,7 +2446,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "array('h', [-2, -1, 1024, 1, 2])"
+      "text/plain": [
+       "array('h', [-2, -1, 1024, 1, 2])"
+      ]
      },
      "execution_count": 88,
      "metadata": {},
@@ -2300,7 +2481,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11])"
+      "text/plain": [
+       "array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11])"
+      ]
      },
      "execution_count": 89,
      "metadata": {},
@@ -2321,7 +2504,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "numpy.ndarray"
+      "text/plain": [
+       "numpy.ndarray"
+      ]
      },
      "execution_count": 90,
      "metadata": {},
@@ -2339,7 +2524,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "(12,)"
+      "text/plain": [
+       "(12,)"
+      ]
      },
      "execution_count": 91,
      "metadata": {},
@@ -2357,7 +2544,11 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "array([[ 0,  1,  2,  3],\n       [ 4,  5,  6,  7],\n       [ 8,  9, 10, 11]])"
+      "text/plain": [
+       "array([[ 0,  1,  2,  3],\n",
+       "       [ 4,  5,  6,  7],\n",
+       "       [ 8,  9, 10, 11]])"
+      ]
      },
      "execution_count": 92,
      "metadata": {},
@@ -2376,7 +2567,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "array([ 8,  9, 10, 11])"
+      "text/plain": [
+       "array([ 8,  9, 10, 11])"
+      ]
      },
      "execution_count": 93,
      "metadata": {},
@@ -2394,7 +2587,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "9"
+      "text/plain": [
+       "9"
+      ]
      },
      "execution_count": 94,
      "metadata": {},
@@ -2412,7 +2607,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "array([1, 5, 9])"
+      "text/plain": [
+       "array([1, 5, 9])"
+      ]
      },
      "execution_count": 95,
      "metadata": {},
@@ -2430,7 +2627,12 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "array([[ 0,  4,  8],\n       [ 1,  5,  9],\n       [ 2,  6, 10],\n       [ 3,  7, 11]])"
+      "text/plain": [
+       "array([[ 0,  4,  8],\n",
+       "       [ 1,  5,  9],\n",
+       "       [ 2,  6, 10],\n",
+       "       [ 3,  7, 11]])"
+      ]
      },
      "execution_count": 96,
      "metadata": {},
@@ -2475,7 +2677,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "array([0.06078257, 0.61741189, 0.84349987])"
+      "text/plain": [
+       "array([0.06078257, 0.61741189, 0.84349987])"
+      ]
      },
      "execution_count": 99,
      "metadata": {},
@@ -2493,7 +2697,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "array([0.03039128, 0.30870594, 0.42174994])"
+      "text/plain": [
+       "array([0.03039128, 0.30870594, 0.42174994])"
+      ]
      },
      "execution_count": 100,
      "metadata": {},
@@ -2512,7 +2718,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "True"
+      "text/plain": [
+       "True"
+      ]
      },
      "execution_count": 101,
      "metadata": {},
@@ -2545,7 +2753,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "memmap([0.06078257, 0.61741189, 0.84349987])"
+      "text/plain": [
+       "memmap([0.06078257, 0.61741189, 0.84349987])"
+      ]
      },
      "execution_count": 103,
      "metadata": {},
@@ -2577,7 +2787,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])"
+      "text/plain": [
+       "deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])"
+      ]
      },
      "execution_count": 104,
      "metadata": {},
@@ -2598,7 +2810,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "deque([7, 8, 9, 0, 1, 2, 3, 4, 5, 6])"
+      "text/plain": [
+       "deque([7, 8, 9, 0, 1, 2, 3, 4, 5, 6])"
+      ]
      },
      "execution_count": 105,
      "metadata": {},
@@ -2617,7 +2831,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "deque([1, 2, 3, 4, 5, 6, 7, 8, 9, 0])"
+      "text/plain": [
+       "deque([1, 2, 3, 4, 5, 6, 7, 8, 9, 0])"
+      ]
      },
      "execution_count": 106,
      "metadata": {},
@@ -2636,7 +2852,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "deque([-1, 1, 2, 3, 4, 5, 6, 7, 8, 9])"
+      "text/plain": [
+       "deque([-1, 1, 2, 3, 4, 5, 6, 7, 8, 9])"
+      ]
      },
      "execution_count": 107,
      "metadata": {},
@@ -2655,7 +2873,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "deque([3, 4, 5, 6, 7, 8, 9, 11, 22, 33])"
+      "text/plain": [
+       "deque([3, 4, 5, 6, 7, 8, 9, 11, 22, 33])"
+      ]
      },
      "execution_count": 108,
      "metadata": {},
@@ -2674,7 +2894,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "deque([40, 30, 20, 10, 3, 4, 5, 6, 7, 8])"
+      "text/plain": [
+       "deque([40, 30, 20, 10, 3, 4, 5, 6, 7, 8])"
+      ]
      },
      "execution_count": 109,
      "metadata": {},
@@ -2743,7 +2965,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, '1', 5, 6, '9', 14, 19, '23', 28, '28']"
+      "text/plain": [
+       "[0, '1', 5, 6, '9', 14, 19, '23', 28, '28']"
+      ]
      },
      "execution_count": 112,
      "metadata": {},
@@ -2763,7 +2987,9 @@
    "outputs": [
     {
      "data": {
-      "text/plain": "[0, '1', 14, 19, '23', 28, '28', 5, 6, '9']"
+      "text/plain": [
+       "[0, '1', 14, 19, '23', 28, '28', 5, 6, '9']"
+      ]
      },
      "execution_count": 113,
      "metadata": {},
@@ -2784,7 +3010,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": ".venv",
    "language": "python",
    "name": "python3"
   },
@@ -2798,9 +3024,9 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.0"
+   "version": "3.12.3"
   }
  },
  "nbformat": 4,
  "nbformat_minor": 2
-}
\ No newline at end of file
+}
diff --git a/02-array-seq/memoryviews.ipynb b/02-array-seq/memoryviews.ipynb
index 860d474..a85ac95 100644
--- a/02-array-seq/memoryviews.ipynb
+++ b/02-array-seq/memoryviews.ipynb
@@ -14,15 +14,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 2,
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "3.7.1 (default, Dec 14 2018, 13:28:58) \n",
-      "[Clang 4.0.1 (tags/RELEASE_401/final)]\n"
+      "3.12.3 (main, Jun 18 2025, 17:59:45) [GCC 13.3.0]\n"
      ]
     }
    ],
@@ -33,16 +32,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 4,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "<memory at 0x1045a31c8>"
+       "<memory at 0x7a59caf7cd00>"
       ]
      },
-     "execution_count": 2,
+     "execution_count": 4,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -54,7 +53,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 5,
    "metadata": {},
    "outputs": [
     {
@@ -63,7 +62,7 @@
        "[35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49]"
       ]
      },
-     "execution_count": 3,
+     "execution_count": 5,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -216,7 +215,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": ".venv",
    "language": "python",
    "name": "python3"
   },
@@ -230,7 +229,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.1"
+   "version": "3.12.3"
   }
  },
  "nbformat": 4,