diff --git a/lesson-02/class_02.ipynb b/lesson-02/class_02.ipynb
new file mode 100644
index 0000000..636638f
--- /dev/null
+++ b/lesson-02/class_02.ipynb
@@ -0,0 +1,2107 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "f0cafd2e-c64a-424a-892c-f9f5faca893a",
+   "metadata": {},
+   "source": [
+    "# try/except example"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 82,
+   "id": "85bab651-3cea-4daa-b452-8d9fbfb73c01",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class ApiError(Exception):\n",
+    "    pass"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 83,
+   "id": "466de340-9f43-4d87-9b98-b6bd3dcc5b46",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "try - enter\n",
+      "Exception err=ApiError()\n",
+      "finally\n"
+     ]
+    },
+    {
+     "ename": "ApiError",
+     "evalue": "",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mApiError\u001b[0m                                  Traceback (most recent call last)",
+      "Cell \u001b[0;32mIn[83], line 3\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[38;5;28;01mtry\u001b[39;00m:\n\u001b[1;32m      2\u001b[0m     \u001b[38;5;28mprint\u001b[39m(\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mtry - enter\u001b[39m\u001b[38;5;124m\"\u001b[39m)\n\u001b[0;32m----> 3\u001b[0m     \u001b[38;5;28;01mraise\u001b[39;00m ApiError()\n\u001b[1;32m      4\u001b[0m \u001b[38;5;28;01mexcept\u001b[39;00m \u001b[38;5;167;01mException\u001b[39;00m \u001b[38;5;28;01mas\u001b[39;00m err:\n\u001b[1;32m      5\u001b[0m     \u001b[38;5;28mprint\u001b[39m(\u001b[38;5;124mf\u001b[39m\u001b[38;5;124m\"\u001b[39m\u001b[38;5;124mException \u001b[39m\u001b[38;5;132;01m{\u001b[39;00merr\u001b[38;5;132;01m=}\u001b[39;00m\u001b[38;5;124m\"\u001b[39m)\n",
+      "\u001b[0;31mApiError\u001b[0m: "
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    print(\"try - enter\")\n",
+    "    raise ApiError()\n",
+    "except Exception as err:\n",
+    "    print(f\"Exception {err=}\")\n",
+    "    raise\n",
+    "except ApiError as err:\n",
+    "    print(f\"ApiError {err=}\")\n",
+    "    raise\n",
+    "else:\n",
+    "    print(\"else\")\n",
+    "finally:\n",
+    "    print(\"finally\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 84,
+   "id": "4bb67d82-f38a-4286-bebb-dd9be2484a8b",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "try - enter\n",
+      "Exception err=ApiError()\n",
+      "finally\n"
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    print(\"try - enter\")\n",
+    "    raise ApiError()\n",
+    "except Exception as err:\n",
+    "    print(f\"Exception {err=}\")\n",
+    "except ApiError as err:\n",
+    "    print(f\"ApiError {err=}\")\n",
+    "else:\n",
+    "    print(\"else\")\n",
+    "finally:\n",
+    "    print(\"finally\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 85,
+   "id": "430067cd-3c69-4c43-ba36-48fc67a2f1ef",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "try - enter\n",
+      "ApiError err=ApiError()\n",
+      "finally\n"
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    print(\"try - enter\")\n",
+    "    raise ApiError()\n",
+    "except ApiError as err:\n",
+    "    print(f\"ApiError {err=}\")\n",
+    "except Exception as err:\n",
+    "    print(f\"Exception {err=}\")\n",
+    "else:\n",
+    "    print(\"else\")\n",
+    "finally:\n",
+    "    print(\"finally\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 86,
+   "id": "e63ef0fc-2dca-4288-99fc-873b2192d424",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "try - enter\n",
+      "Exception err=ValueError()\n",
+      "finally\n"
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    print(\"try - enter\")\n",
+    "    raise ValueError()\n",
+    "except ApiError as err:\n",
+    "    print(f\"ApiError {err=}\")\n",
+    "except Exception as err:\n",
+    "    print(f\"Exception {err=}\")\n",
+    "else:\n",
+    "    print(\"else\")\n",
+    "finally:\n",
+    "    print(\"finally\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c263f985-cfee-4ed6-8f3e-fccb49b6f41d",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "try:\n",
+    "    print(\"try - enter\")\n",
+    "    raise ValueError()\n",
+    "except ApiError as err:\n",
+    "    print(f\"ApiError {err=}\")\n",
+    "except Exception as err:\n",
+    "    print(f\"Exception {err=}\")\n",
+    "else:\n",
+    "    print(\"else\")\n",
+    "finally:\n",
+    "    print(\"finally\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c07eefc2-ada1-4e47-b0f4-f5f0d668a94a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "\n",
+    "file = open()\n",
+    "for line in file:\n",
+    "    raise Exception()\n",
+    "    print()\n",
+    "\n",
+    "file.close()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7964e24e-3a6e-42b3-9bd2-d832717404e8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "try:\n",
+    "    file = open()\n",
+    "    for line in file:\n",
+    "        raise Exception()\n",
+    "        print()\n",
+    "finally:\n",
+    "    file.close()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 87,
+   "id": "28ee1930-c49e-4a01-a8b0-a7d7d17ec441",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "try - enter\n",
+      "else\n",
+      "finally\n"
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    print(\"try - enter\")\n",
+    "except ApiError as err:\n",
+    "    print(f\"ApiError {err=}\")\n",
+    "except Exception as err:\n",
+    "    print(f\"Exception {err=}\")\n",
+    "else:\n",
+    "    print(\"else\")\n",
+    "finally:\n",
+    "    print(\"finally\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "32284423-7334-4454-9e4f-6fc1981d71bc",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7b89c773-0c4e-4db8-8c4e-9963ff3067f8",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "markdown",
+   "id": "24208b3d-de56-4092-a0c5-d896e9a5c6ac",
+   "metadata": {},
+   "source": [
+    "# Рекурсия"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "81c8e7aa-29fa-4f55-b31f-a7b0ec39ce22",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def calc_factorial(n):\n",
+    "    if n == 0:\n",
+    "        return 1\n",
+    "    return n * calc_factorial(n - 1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "abdad667-808a-47f2-8a4e-f37b5a185549",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(3628800, 120)"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "calc_factorial(10), calc_factorial(5)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "27565db2-4ece-4249-8138-690b0d0fb8d5",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def counter(n):\n",
+    "    if n == 0:\n",
+    "        return 0\n",
+    "    return n + counter(n - 1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "id": "4d401527-8614-4263-9290-f3c3cba0a732",
+   "metadata": {},
+   "outputs": [
+    {
+     "ename": "RecursionError",
+     "evalue": "maximum recursion depth exceeded",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mRecursionError\u001b[0m                            Traceback (most recent call last)",
+      "Cell \u001b[0;32mIn[14], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mcounter\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;241;43m2990\u001b[39;49m\u001b[43m)\u001b[49m\n",
+      "Cell \u001b[0;32mIn[4], line 4\u001b[0m, in \u001b[0;36mcounter\u001b[0;34m(n)\u001b[0m\n\u001b[1;32m      2\u001b[0m \u001b[38;5;28;01mif\u001b[39;00m n \u001b[38;5;241m==\u001b[39m \u001b[38;5;241m0\u001b[39m:\n\u001b[1;32m      3\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;241m0\u001b[39m\n\u001b[0;32m----> 4\u001b[0m \u001b[38;5;28;01mreturn\u001b[39;00m n \u001b[38;5;241m+\u001b[39m \u001b[43mcounter\u001b[49m\u001b[43m(\u001b[49m\u001b[43mn\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m-\u001b[39;49m\u001b[43m \u001b[49m\u001b[38;5;241;43m1\u001b[39;49m\u001b[43m)\u001b[49m\n",
+      "Cell \u001b[0;32mIn[4], line 4\u001b[0m, in \u001b[0;36mcounter\u001b[0;34m(n)\u001b[0m\n\u001b[1;32m      2\u001b[0m \u001b[38;5;28;01mif\u001b[39;00m n \u001b[38;5;241m==\u001b[39m \u001b[38;5;241m0\u001b[39m:\n\u001b[1;32m      3\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;241m0\u001b[39m\n\u001b[0;32m----> 4\u001b[0m \u001b[38;5;28;01mreturn\u001b[39;00m n \u001b[38;5;241m+\u001b[39m \u001b[43mcounter\u001b[49m\u001b[43m(\u001b[49m\u001b[43mn\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m-\u001b[39;49m\u001b[43m \u001b[49m\u001b[38;5;241;43m1\u001b[39;49m\u001b[43m)\u001b[49m\n",
+      "    \u001b[0;31m[... skipping similar frames: counter at line 4 (2974 times)]\u001b[0m\n",
+      "Cell \u001b[0;32mIn[4], line 4\u001b[0m, in \u001b[0;36mcounter\u001b[0;34m(n)\u001b[0m\n\u001b[1;32m      2\u001b[0m \u001b[38;5;28;01mif\u001b[39;00m n \u001b[38;5;241m==\u001b[39m \u001b[38;5;241m0\u001b[39m:\n\u001b[1;32m      3\u001b[0m     \u001b[38;5;28;01mreturn\u001b[39;00m \u001b[38;5;241m0\u001b[39m\n\u001b[0;32m----> 4\u001b[0m \u001b[38;5;28;01mreturn\u001b[39;00m n \u001b[38;5;241m+\u001b[39m \u001b[43mcounter\u001b[49m\u001b[43m(\u001b[49m\u001b[43mn\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m-\u001b[39;49m\u001b[43m \u001b[49m\u001b[38;5;241;43m1\u001b[39;49m\u001b[43m)\u001b[49m\n",
+      "\u001b[0;31mRecursionError\u001b[0m: maximum recursion depth exceeded"
+     ]
+    }
+   ],
+   "source": [
+    "counter(2990)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "id": "642cd1d8-0304-4ca6-8467-ff1aecf4fc66",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "3000"
+      ]
+     },
+     "execution_count": 9,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "import sys\n",
+    "sys.getrecursionlimit()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "id": "76ddf4fd-61f7-41ee-9b1c-ec01f3f73cfc",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "sys.setrecursionlimit(5000)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "id": "539163be-a51d-4d89-b5af-3e72efa9bce2",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "4501500"
+      ]
+     },
+     "execution_count": 16,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "counter(3000)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "b19b5cf0-df12-43c8-ac72-79cbdc52a2b1",
+   "metadata": {},
+   "source": [
+    "# Параметры и аргументы функций"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "id": "e109c7b4-026b-468a-9549-e243d38bc2ad",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def fn1(x, y=100):\n",
+    "    return x + y"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "id": "5d7ac51b-07c0-4a4b-bae7-eaa05a00ba21",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(110, 30, 110, 30, 30)"
+      ]
+     },
+     "execution_count": 20,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "fn1(10), fn1(10, 20), fn1(x=10), fn1(x=10, y=20), fn1(y=20, x=10)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "id": "79f0208b-aca5-40dd-b45c-231472c0a73a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def fn2(*args, **kwargs):\n",
+    "    print(args, kwargs)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 23,
+   "id": "c158a07a-ea7e-4b45-8ca7-1a60ebc9ddef",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "() {}\n",
+      "(1, 2, 3) {'k': 10, 'args': 20}\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "(None, None)"
+      ]
+     },
+     "execution_count": 23,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "fn2(), fn2(1, 2, 3, k=10, args=20)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 24,
+   "id": "f53f990c-3a88-4936-abf5-3197ef5ac2a2",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "\u001b[0;31mSignature:\u001b[0m \u001b[0mlen\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mobj\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0;34m/\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
+       "\u001b[0;31mDocstring:\u001b[0m Return the number of items in a container.\n",
+       "\u001b[0;31mType:\u001b[0m      builtin_function_or_method"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "len?"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "id": "71adadb0-8140-4024-aee6-e29542e4bc18",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "0"
+      ]
+     },
+     "execution_count": 26,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "len([])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 27,
+   "id": "1547c838-f5b2-4423-8c03-b2fdcf133519",
+   "metadata": {},
+   "outputs": [
+    {
+     "ename": "TypeError",
+     "evalue": "len() takes no keyword arguments",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
+      "Cell \u001b[0;32mIn[27], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[38;5;28;43mlen\u001b[39;49m\u001b[43m(\u001b[49m\u001b[43mobj\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[43m[\u001b[49m\u001b[43m]\u001b[49m\u001b[43m)\u001b[49m\n",
+      "\u001b[0;31mTypeError\u001b[0m: len() takes no keyword arguments"
+     ]
+    }
+   ],
+   "source": [
+    "len(obj=[])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "id": "9dc77bd6-2195-4511-9512-e2b95c7bad18",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def fn7(pos1, /, pos2, pos3=3, *, kw1=11, **kwargs):\n",
+    "    print(f\"{pos1=}, {pos2=}, {pos3=}, {kw1=}, {kwargs=}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 31,
+   "id": "36fad21d-8614-4203-af48-17def2786430",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "pos1=10, pos2=20, pos3=3, kw1=11, kwargs={}\n"
+     ]
+    }
+   ],
+   "source": [
+    "fn7(10, pos2=20)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 32,
+   "id": "91bd03c1-1dcb-471f-a516-82a358585d21",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "pos1=10, pos2=20, pos3=30, kw1=11, kwargs={}\n"
+     ]
+    }
+   ],
+   "source": [
+    "fn7(10, 20, 30)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 33,
+   "id": "4fa3e30b-dcbf-462f-8c1c-3a04e7ff50d1",
+   "metadata": {},
+   "outputs": [
+    {
+     "ename": "TypeError",
+     "evalue": "fn7() takes from 2 to 3 positional arguments but 4 were given",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
+      "Cell \u001b[0;32mIn[33], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mfn7\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;241;43m10\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m20\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m30\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m40\u001b[39;49m\u001b[43m)\u001b[49m\n",
+      "\u001b[0;31mTypeError\u001b[0m: fn7() takes from 2 to 3 positional arguments but 4 were given"
+     ]
+    }
+   ],
+   "source": [
+    "fn7(10, 20, 30, 40)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 34,
+   "id": "fb0d6d92-eea3-4190-9602-f1d19b99812d",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "pos1=10, pos2=20, pos3=30, kw1=40, kwargs={}\n"
+     ]
+    }
+   ],
+   "source": [
+    "fn7(10, 20, 30, kw1=40)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
+   "id": "a444e466-7b9b-4cf7-aba6-8ea39b71c004",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "pos1=10, pos2=20, pos3=30, kw1=40, kwargs={'key': 50, 'val': 90}\n"
+     ]
+    }
+   ],
+   "source": [
+    "fn7(10, 20, 30, kw1=40, key=50, val=90)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "id": "fcbd7719-4ff6-40cb-bf76-cf1584d85051",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def fn8(pos1, /, pos2, pos3=3, *args, kw1=11, **kwargs):\n",
+    "    print(f\"{pos1=}, {pos2=}, {pos3=}, {args=}, {kw1=}, {kwargs=}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 37,
+   "id": "316bf871-cfc3-4991-ae33-658b38056e2c",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "pos1=10, pos2=20, pos3=30, args=(), kw1=40, kwargs={'key': 50, 'val': 90}\n"
+     ]
+    }
+   ],
+   "source": [
+    "fn8(10, 20, 30, kw1=40, key=50, val=90)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 38,
+   "id": "3039326a-0dfb-40f7-be4e-2b657213c2b4",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "pos1=10, pos2=20, pos3=30, args=(40,), kw1=11, kwargs={'key': 50, 'val': 90}\n"
+     ]
+    }
+   ],
+   "source": [
+    "fn8(10, 20, 30, 40, key=50, val=90)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 39,
+   "id": "423114c1-2e67-4b7f-bcbf-933e77b74f40",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "pos1=10, pos2=20, pos3=30, args=(40, 41, 42, 43), kw1=44, kwargs={'key': 50, 'val': 90}\n"
+     ]
+    }
+   ],
+   "source": [
+    "fn8(10, 20, 30, 40, 41, 42, 43, kw1=44, key=50, val=90)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "93d4e99a-ca53-41e7-846b-99a855d3cec2",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 40,
+   "id": "c4ea2696-b69d-4a60-986e-f5dd2295a23f",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def double_param(x, **kwargs):\n",
+    "    print(f\"{x=}, {kwargs=}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "id": "d91c919d-bc45-4e92-8d03-bd13888fc5b0",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "x=10, kwargs={'y': 20}\n"
+     ]
+    }
+   ],
+   "source": [
+    "double_param(10, y=20)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "id": "2ac7609e-cac9-4339-a07d-7410ea3bbf6f",
+   "metadata": {},
+   "outputs": [
+    {
+     "ename": "TypeError",
+     "evalue": "double_param() got multiple values for argument 'x'",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
+      "Cell \u001b[0;32mIn[42], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mdouble_param\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;241;43m10\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[43mx\u001b[49m\u001b[38;5;241;43m=\u001b[39;49m\u001b[38;5;241;43m20\u001b[39;49m\u001b[43m)\u001b[49m\n",
+      "\u001b[0;31mTypeError\u001b[0m: double_param() got multiple values for argument 'x'"
+     ]
+    }
+   ],
+   "source": [
+    "double_param(10, x=20)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 43,
+   "id": "dcb5925f-421f-4e54-9972-fc9d2c5be0f6",
+   "metadata": {},
+   "outputs": [
+    {
+     "ename": "TypeError",
+     "evalue": "double_param() got multiple values for argument 'x'",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
+      "Cell \u001b[0;32mIn[43], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mdouble_param\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;241;43m10\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m*\u001b[39;49m\u001b[38;5;241;43m*\u001b[39;49m\u001b[43m{\u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mx\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m:\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m20\u001b[39;49m\u001b[43m}\u001b[49m\u001b[43m)\u001b[49m\n",
+      "\u001b[0;31mTypeError\u001b[0m: double_param() got multiple values for argument 'x'"
+     ]
+    }
+   ],
+   "source": [
+    "double_param(10, **{\"x\": 20})"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 44,
+   "id": "5667f1f3-8b62-4ac6-a584-2b3a54cc4f92",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def double_param_fixed(x, /, **kwargs):\n",
+    "    print(f\"{x=}, {kwargs=}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 45,
+   "id": "a926d878-d068-44f2-97ff-e10aabd051e7",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "x=10, kwargs={'x': 20}\n"
+     ]
+    }
+   ],
+   "source": [
+    "double_param_fixed(10, x=20)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "979a7589-cbd7-438c-bf17-23bf686a031a",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "markdown",
+   "id": "1443b29b-5ec9-4c12-bd85-92397debd3b3",
+   "metadata": {},
+   "source": [
+    "# параметры по умоолчанию"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 47,
+   "id": "7fe2f46f-dbc9-480d-bd01-adfabbae4985",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def append_to_list(new_val, lst=[1, 2]):\n",
+    "    lst.append(new_val)\n",
+    "    return lst"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 48,
+   "id": "917d2f5e-4b01-4be0-b38e-7335b2400339",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[10]"
+      ]
+     },
+     "execution_count": 48,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "lst = []\n",
+    "\n",
+    "append_to_list(10, lst)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 51,
+   "id": "847af802-dbef-422c-853a-7adbeccb3722",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "arr1 = append_to_list(10)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 52,
+   "id": "5dccd221-2706-45bf-a08b-924805c1ac8a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "arr2 = append_to_list(20)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 53,
+   "id": "1a3d8a2d-bd17-4361-b602-fc2d4659e8ee",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(True, True, [1, 2, 10, 20, 10, 20], [1, 2, 10, 20, 10, 20])"
+      ]
+     },
+     "execution_count": 53,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "arr1 == arr2, arr1 is arr2, arr1, arr2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 56,
+   "id": "d6bf22a3-2f47-474a-bc66-c84c8e4e2a5d",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1, 2, 10, 20, 10, 20, 10, 10, 50, 50, 99]"
+      ]
+     },
+     "execution_count": 56,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "append_to_list(99)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 57,
+   "id": "e49f5526-da38-4c9a-a47b-fd1e6bc4b764",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1, 2, 10, 20, 10, 20, 10, 10, 50, 50, 99, 99]"
+      ]
+     },
+     "execution_count": 57,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "append_to_list(99)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "9b50a81a-6335-4b98-9603-da0059a26638",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "0cc1928b-9aa7-4e97-a7f4-5c7efd172c0c",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 59,
+   "id": "b943fc01-763a-42d6-9a38-78136232f736",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def append_to_list_correct(new_val, lst=None):\n",
+    "    if lst is None:\n",
+    "        lst = [1, 2]\n",
+    "\n",
+    "    lst.append(new_val)\n",
+    "    \n",
+    "    return lst"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 61,
+   "id": "582d86e0-ecc3-45c4-8b62-9d3153483717",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1, 2, 99]"
+      ]
+     },
+     "execution_count": 61,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "append_to_list_correct(99)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 62,
+   "id": "2a374ddd-42e1-4d29-8807-079dd39f093e",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1, 2, 99]"
+      ]
+     },
+     "execution_count": 62,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "append_to_list_correct(99)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 63,
+   "id": "fe33685b-4b8b-4063-a6d5-92206fb295cf",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "False"
+      ]
+     },
+     "execution_count": 63,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "append_to_list_correct(100) is append_to_list_correct(100)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 65,
+   "id": "cf0d72bc-fb12-4a34-b92e-e04c0f159777",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[10, 20, 30, 40]"
+      ]
+     },
+     "execution_count": 65,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "append_to_list_correct(40, [10, 20, 30])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c0c1ab7f-5065-464d-a43e-bf6eb36f6b6b",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "208c6f03-6791-4f9a-a93f-eeefcfa13cf8",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "markdown",
+   "id": "831a0e00-967b-4ee8-9623-aba42153369a",
+   "metadata": {},
+   "source": [
+    "# передача аргументов"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 66,
+   "id": "fa5be512-543b-4d38-9188-a0d6d406315e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def fn(param):\n",
+    "    param = 20\n",
+    "    return param"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 68,
+   "id": "c5b656a2-c2d5-4a27-ae69-ae44f4d58678",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "10\n"
+     ]
+    }
+   ],
+   "source": [
+    "arg = 10\n",
+    "\n",
+    "fn(arg)  # param = arg\n",
+    "\n",
+    "print(f\"{arg}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 69,
+   "id": "b2ae9f4d-85a6-4d2a-8b0b-337da623261b",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[99, 10]\n"
+     ]
+    }
+   ],
+   "source": [
+    "def fn_mutable(param: list[int]):\n",
+    "    param.append(10)\n",
+    "    return param\n",
+    "\n",
+    "arg = [99]\n",
+    "\n",
+    "fn_mutable(arg)  # param = arg\n",
+    "\n",
+    "print(f\"{arg}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "1d0f029f-43ff-46ee-8de8-40845f0d07ec",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 70,
+   "id": "be7773e3-5219-4ab6-838f-1fe87c374e88",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[99]\n"
+     ]
+    }
+   ],
+   "source": [
+    "def fn_mutable(param: list[int]):\n",
+    "    param = []\n",
+    "    return param\n",
+    "\n",
+    "arg = [99]\n",
+    "\n",
+    "fn_mutable(arg)  # param = arg\n",
+    "\n",
+    "print(f\"{arg}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 71,
+   "id": "a50931da-899b-440f-aedc-9cc7f7ebcde8",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[]\n"
+     ]
+    }
+   ],
+   "source": [
+    "def fn_mutable(param: list[int]):\n",
+    "    global arg\n",
+    "    arg = []\n",
+    "    return param\n",
+    "\n",
+    "arg = [99]\n",
+    "\n",
+    "fn_mutable(arg)  # param = arg\n",
+    "\n",
+    "print(f\"{arg}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "ec7598b8-1c0f-4ede-a278-4634551c0cef",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "a033f177-a302-41b4-b657-75c18139181a",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 73,
+   "id": "12621107-fee6-42d2-af2b-78bbb25e20d7",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "lst = list(range(-10, 10))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 74,
+   "id": "bf92348c-c65a-40ee-ab9d-8304710f7c90",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
+      ]
+     },
+     "execution_count": 74,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "sorted(lst)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 76,
+   "id": "c60d4a08-8038-48e7-9895-9614bbfd96f0",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[0, -1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7, -8, 8, -9, 9, -10]"
+      ]
+     },
+     "execution_count": 76,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "sorted(lst, key=lambda x: x ** 2)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 77,
+   "id": "2ecfb571-f0f8-4c7e-ae48-7e192971b09e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "lst1 = list(range(-10, 10))\n",
+    "lst2 = list(range(-10, 10))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 81,
+   "id": "2e469eeb-39e5-4d7c-9775-8e632e84a269",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "([0, -1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7, -8, 8, -9, 9, -10],\n",
+       " [0, -1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7, -8, 8, -9, 9, -10])"
+      ]
+     },
+     "execution_count": 81,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "sort_key = lambda x: x ** 2  # NONONO!\n",
+    "\n",
+    "sorted(lst1, key=sort_key), sorted(lst2, key=sort_key)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 80,
+   "id": "8204807d-9520-4790-8201-964e687cd56e",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "([0, -1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7, -8, 8, -9, 9, -10],\n",
+       " [0, -1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7, -8, 8, -9, 9, -10])"
+      ]
+     },
+     "execution_count": 80,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "def sort_key(x):\n",
+    "    return x ** 2\n",
+    "\n",
+    "sorted(lst1, key=sort_key), sorted(lst2, key=sort_key)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "18b71ab6-2871-4366-9636-6ebdd562a888",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 88,
+   "id": "da2e2f8b-ed2f-4c00-8b96-769ce7120846",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "True"
+      ]
+     },
+     "execution_count": 88,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "\"abc\" in \"abc\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 90,
+   "id": "4959a1bd-5b8c-4da7-aae3-e2f9b1f46fd6",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "True False\n"
+     ]
+    }
+   ],
+   "source": [
+    "def search_substring(haystack: str, needle: str) -> bool:\n",
+    "    return needle.lower() in haystack.lower()\n",
+    "\n",
+    "\n",
+    "print(search_substring(\"aBc\", \"Ab\"), search_substring(\"abc\", \"Ac\"))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 102,
+   "id": "8c0cefd3-652c-46b8-89a1-5d00b048e39a",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stderr",
+     "output_type": "stream",
+     "text": [
+      "test_search_bad_param (__main__.TestSearchSubstring.test_search_bad_param) ... ok\n",
+      "test_search_invalid (__main__.TestSearchSubstring.test_search_invalid) ... ok\n",
+      "test_search_valid (__main__.TestSearchSubstring.test_search_valid) ... ok\n",
+      "\n",
+      "----------------------------------------------------------------------\n",
+      "Ran 3 tests in 0.007s\n",
+      "\n",
+      "OK\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "<unittest.main.TestProgram at 0x10e327020>"
+      ]
+     },
+     "execution_count": 102,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "import unittest\n",
+    "\n",
+    "\n",
+    "class TestSearchSubstring(unittest.TestCase):\n",
+    "    def test_search_valid(self):\n",
+    "        self.assertTrue(search_substring(\"aBc\", \"Ab\"))\n",
+    "        self.assertTrue(search_substring(\"aBc\", \"\"))\n",
+    "        self.assertTrue(search_substring(\"\", \"\"))\n",
+    "        \n",
+    "        self.assertTrue(search_substring(\"a\", \"A\"))\n",
+    "        self.assertTrue(search_substring(\"a\", \"a\"))\n",
+    "        self.assertTrue(search_substring(\"A\", \"a\"))\n",
+    "        \n",
+    "        self.assertTrue(search_substring(\"abc\", \"a\"))\n",
+    "        self.assertTrue(search_substring(\"cba\", \"a\"))\n",
+    "\n",
+    "        self.assertTrue(search_substring(\"aabbaa\", \"aa\"))\n",
+    "        self.assertTrue(search_substring(\"CCAABBaa\", \"AA\"))\n",
+    "        self.assertTrue(search_substring(\"CCAABBaa\", \"CCAABBaa\"))\n",
+    "        self.assertTrue(search_substring(\"CCAABBaa\", \"ccAAbbaa\"))\n",
+    "\n",
+    "    def test_search_invalid(self):\n",
+    "        self.assertFalse(search_substring(\"abc\", \"Ac\"))\n",
+    "        self.assertFalse(search_substring(\"\", \"a\"))\n",
+    "\n",
+    "        self.assertFalse(search_substring(\"n\", \"A\"))\n",
+    "        self.assertFalse(search_substring(\"N\", \"a\"))\n",
+    "        self.assertFalse(search_substring(\"NBdop\", \"a\"))\n",
+    "    \n",
+    "        self.assertFalse(search_substring(\"ab\", \"abc\"))\n",
+    "\n",
+    "        self.assertFalse(search_substring(\"CCAABBan\", \"ccAAbbaa\"))\n",
+    "        self.assertFalse(search_substring(\"tCAABBaa\", \"ccAAbbaa\"))\n",
+    "    \n",
+    "    def test_search_bad_param(self):\n",
+    "        with self.assertRaises(AttributeError):\n",
+    "           search_substring(\"abc\", None)\n",
+    "\n",
+    "\n",
+    "unittest.main(argv=[''], verbosity=2, exit=False)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "84ca8269-b230-4918-bf91-b2977f8d132e",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "af4a35ae-08d6-4f41-9055-40fc552fa2d4",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "cee7b065-0f65-4d61-86e5-077a17a7ee66",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 105,
+   "id": "9d1729a8-c4e0-4837-a782-a7c9a6f78191",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "5\n",
+      "5\n",
+      "5\n",
+      "5\n",
+      "5\n"
+     ]
+    }
+   ],
+   "source": [
+    "functions = [lambda x: a for a in range(1, 6)]\n",
+    "\n",
+    "obj = 0\n",
+    "\n",
+    "for fn in functions:\n",
+    "    obj = fn(obj)\n",
+    "    print(obj)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 107,
+   "id": "1b0d50b8-8fec-4b7c-9a66-e6451292a1f2",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "5\n",
+      "5\n",
+      "5\n",
+      "5\n",
+      "5\n"
+     ]
+    }
+   ],
+   "source": [
+    "a = 10\n",
+    "\n",
+    "for fn in functions:\n",
+    "    obj = fn(obj)\n",
+    "    print(obj)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 109,
+   "id": "43b87153-5fec-49ab-ae2b-8261943f74b4",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "5\n",
+      "5\n",
+      "5\n",
+      "5\n",
+      "5\n"
+     ]
+    }
+   ],
+   "source": [
+    "functions = []\n",
+    "\n",
+    "for a in range(1, 6):\n",
+    "    functions.append(lambda x: a)\n",
+    "\n",
+    "obj = 0\n",
+    "\n",
+    "for fn in functions:\n",
+    "    obj = fn(obj)\n",
+    "    print(obj)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 110,
+   "id": "3d128966-753e-449d-9214-b7a26fa6707e",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "10\n",
+      "10\n",
+      "10\n",
+      "10\n",
+      "10\n"
+     ]
+    }
+   ],
+   "source": [
+    "a = 10\n",
+    "\n",
+    "for fn in functions:\n",
+    "    obj = fn(obj)\n",
+    "    print(obj)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 111,
+   "id": "540d8b00-cd0a-4486-a2a7-0b7a1926dc97",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "str\n",
+      "str\n",
+      "str\n",
+      "str\n",
+      "str\n"
+     ]
+    }
+   ],
+   "source": [
+    "a = \"str\"\n",
+    "\n",
+    "for fn in functions:\n",
+    "    obj = fn(obj)\n",
+    "    print(obj)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 114,
+   "id": "2d1c7697-1504-495a-8d4d-3b47a04b7035",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "1\n",
+      "2\n",
+      "3\n",
+      "4\n",
+      "5\n"
+     ]
+    }
+   ],
+   "source": [
+    "functions = [lambda x=a: x for a in range(1, 6)]\n",
+    "\n",
+    "obj = 0\n",
+    "\n",
+    "for fn in functions:\n",
+    "    obj = fn()\n",
+    "    print(obj)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "26b66058-6da9-45b3-94a7-e55146db3aab",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "027750e3-ccec-430b-9054-f5b0b7b8aaff",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 121,
+   "id": "df82b910-1648-4334-a29f-252eb7ff9ffe",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from time import time\n",
+    "\n",
+    "\n",
+    "def deco(fn):\n",
+    "    def inner(*args, **kwargs):\n",
+    "        t1 = time()\n",
+    "        res = fn(*args, **kwargs)\n",
+    "        t2 = time()\n",
+    "        print(fn.__name__, t2 - t1)\n",
+    "        return res\n",
+    "    return inner\n",
+    "\n",
+    "\n",
+    "@deco\n",
+    "def add(a, b):\n",
+    "    return a + b\n",
+    "\n",
+    "\n",
+    "def sub(a, b):\n",
+    "    return a - b\n",
+    "\n",
+    "sub = deco(sub)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 116,
+   "id": "bd8cdc27-586f-4c99-a4f2-d529a753a056",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "add 9.5367431640625e-07\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "5"
+      ]
+     },
+     "execution_count": 116,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add(2, 3)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 118,
+   "id": "d0c01d7e-a3ac-4ff9-b5f5-48fe9941dadb",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "sub 1.1920928955078125e-06\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "-1"
+      ]
+     },
+     "execution_count": 118,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "sub(2, 3)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 119,
+   "id": "cf394baf-f8a0-4aa4-b6f2-5cd8835c6c6d",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "(<function __main__.deco.<locals>.inner(*args, **kwargs)>,\n",
+       " <function __main__.deco.<locals>.inner(*args, **kwargs)>)"
+      ]
+     },
+     "execution_count": 119,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add, sub"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 120,
+   "id": "941b3ca5-17cd-4dc5-b112-b1514da606a6",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'inner'"
+      ]
+     },
+     "execution_count": 120,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add.__name__"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 126,
+   "id": "f16b8767-00b5-4a2e-9e6c-78a6b0a80653",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "<function __main__.add(a, b)>"
+      ]
+     },
+     "execution_count": 126,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add.__closure__[0].cell_contents"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 127,
+   "id": "c129d4a7-1b71-40b1-a568-e148d7f3fb76",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from time import time\n",
+    "from functools import wraps\n",
+    "\n",
+    "\n",
+    "def deco_wraps(fn):\n",
+    "    @wraps(fn)\n",
+    "    def inner(*args, **kwargs):\n",
+    "        t1 = time()\n",
+    "        res = fn(*args, **kwargs)\n",
+    "        t2 = time()\n",
+    "        print(fn.__name__, t2 - t1)\n",
+    "        return res\n",
+    "    return inner\n",
+    "\n",
+    "\n",
+    "@deco_wraps\n",
+    "def add(a, b):\n",
+    "    return a + b\n",
+    "\n",
+    "\n",
+    "def sub(a, b):\n",
+    "    return a - b\n",
+    "\n",
+    "sub = deco_wraps(sub)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 128,
+   "id": "1bcd37dc-a255-4898-8e9d-ef6e6bb8d061",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "add 9.5367431640625e-07\n",
+      "sub 9.5367431640625e-07\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "(4, -5)"
+      ]
+     },
+     "execution_count": 128,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add(1, 3), sub(3, 8)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 129,
+   "id": "414c048a-c360-41bd-9d8d-6c5185924bcc",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'add'"
+      ]
+     },
+     "execution_count": 129,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add.__name__"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 130,
+   "id": "02df674d-6a8e-4c0a-8528-bd92adf3c261",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "<function __main__.add(a, b)>"
+      ]
+     },
+     "execution_count": 130,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add.__wrapped__"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "6e349612-d676-43cb-815f-c2e85c784bd7",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "ac62121e-3c38-4b3e-ac48-18296503040a",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "9138a832-80ce-4445-b937-dee929132859",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 139,
+   "id": "72dbc281-b198-4c98-8880-94553fe8327f",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from time import time\n",
+    "from functools import wraps\n",
+    "\n",
+    "\n",
+    "def limited_deco(limit=10):\n",
+    "    def deco_wraps(fn):\n",
+    "        times = []\n",
+    "\n",
+    "        @wraps(fn)\n",
+    "        def inner(*args, **kwargs):\n",
+    "            t1 = time()\n",
+    "            res = fn(*args, **kwargs)\n",
+    "            t2 = time()\n",
+    "            times.append(t2 - t1)\n",
+    "\n",
+    "            if len(times) > limit:\n",
+    "                times.pop(0)\n",
+    "\n",
+    "            print(fn.__name__, times)\n",
+    "            return res\n",
+    "\n",
+    "        return inner\n",
+    "\n",
+    "    return deco_wraps\n",
+    "\n",
+    "\n",
+    "@limited_deco(3)\n",
+    "def add(a, b):\n",
+    "    return a + b\n",
+    "\n",
+    "\n",
+    "def sub(a, b):\n",
+    "    return a - b\n",
+    "\n",
+    "sub = limited_deco(2)(sub)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 140,
+   "id": "152a7ea8-f3e4-4196-a9e1-a6d1b5eb3f19",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "add [1.6689300537109375e-06]\n",
+      "add [1.6689300537109375e-06, 9.5367431640625e-07]\n",
+      "add [1.6689300537109375e-06, 9.5367431640625e-07, 0.0]\n",
+      "add [9.5367431640625e-07, 0.0, 0.0]\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "(3, 5, 7, 11)"
+      ]
+     },
+     "execution_count": 140,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add(1, 2), add(2, 3), add(3, 4), add(5, 6)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 136,
+   "id": "de569536-aa0d-4d48-83c1-5fa58f321f5a",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "add [9.5367431640625e-07, 2.1457672119140625e-06]\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "6"
+      ]
+     },
+     "execution_count": 136,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "add(1, 5)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 141,
+   "id": "e10dc07b-26c0-4184-894e-316658ed23b8",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "sub [1.9073486328125e-06]\n",
+      "sub [1.9073486328125e-06, 9.5367431640625e-07]\n",
+      "sub [9.5367431640625e-07, 9.5367431640625e-07]\n",
+      "sub [9.5367431640625e-07, 9.5367431640625e-07]\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "(-1, -1, -1, -1)"
+      ]
+     },
+     "execution_count": 141,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "sub(1, 2), sub(2, 3), sub(3, 4), sub(5, 6)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b5af6b38-e70d-4eef-81c0-5bb8717b33b9",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.12.5"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}