284 lines
6.3 KiB
Plaintext
284 lines
6.3 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"id": "02e68cf1",
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"metadata": {},
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"source": [
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"# More Decorator Examples\n",
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"\n",
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"Some additional examples beyond what is in 08.decorators."
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]
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},
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{
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"cell_type": "markdown",
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"id": "b985a33b",
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"metadata": {},
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"source": [
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"## Modifying Arguments within newfunc"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"id": "31c291f2",
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"metadata": {},
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"outputs": [],
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"source": [
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"def reverse_args(func):\n",
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" def newfunc(*args):\n",
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" # within newfunc we are able to write whatever we'd like\n",
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" # we could decide that we want to reverse the arguments\n",
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" reversed_args = reversed(args)\n",
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" return func(*reversed_args)\n",
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" return newfunc\n",
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"\n",
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"\n",
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"@reverse_args\n",
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"def print_args(*args):\n",
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" for arg in args:\n",
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" print(arg)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 2,
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"id": "413cfac8",
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"3\n",
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"2\n",
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"1\n"
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]
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}
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],
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"source": [
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"print_args(1, 2, 3)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 3,
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"id": "95e01cf9",
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"metadata": {},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"0.2"
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]
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},
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"execution_count": 3,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"@reverse_args\n",
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"def divide(a, b):\n",
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" return a / b\n",
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"\n",
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"divide(10, 2)"
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]
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},
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{
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"cell_type": "markdown",
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"id": "d055880d",
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"metadata": {},
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"source": [
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"## Example: Authorization"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 4,
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"id": "1590c5de",
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"metadata": {},
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"outputs": [],
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"source": [
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"# perhaps we want a function that checks if a user can perform an action\n",
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"def auth_required(func):\n",
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" \n",
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" # list of allowed users. in practice, we'd look this up in a database\n",
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" allowed_users = (\"lauren\", \"mitch\")\n",
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" \n",
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" def newfunc(*args, **kwargs):\n",
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" # here, we're actually using an argument within newfunc\n",
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" # by checking if it is in the kwargs dictionary\n",
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" if kwargs.get(\"auth_user\") in allowed_users:\n",
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" func(*args, **kwargs)\n",
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" else:\n",
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" print(\"ACCESS DENIED\")\n",
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" return newfunc\n",
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"\n",
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"# these functions must also accept auth_user so that the above call to func(*args, **kwargs)\n",
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"# doesn't send an invalid parameter through\n",
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"@auth_required\n",
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"def withdraw_funds(account, amount, auth_user):\n",
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" print(f\"withdrew {amount} funds from account={account}\")\n",
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"\n",
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"@auth_required\n",
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"def delete_account(account, auth_user):\n",
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" print(\"deleted\", account)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 5,
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"id": "f9e8bcd0",
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"withdrew 100 funds from account=jim\n"
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]
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}
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],
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"source": [
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"withdraw_funds(\"jim\", 100, auth_user=\"lauren\")"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 6,
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"id": "77a82ae4",
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"ACCESS DENIED\n"
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]
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}
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],
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"source": [
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"delete_account(\"kevin\", auth_user=\"jim\")"
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]
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},
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{
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"cell_type": "markdown",
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"id": "cf9a611a",
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"metadata": {},
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"source": [
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"## Modifying Keyword Parameters"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 7,
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"id": "90161162",
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"metadata": {},
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"outputs": [],
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"source": [
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"# if we didn't want auth_user to be passed through, we'd make a small modification to newfunc\n",
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"\n",
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"def auth_required(func): \n",
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" allowed_users = (\"lauren\", \"mitch\")\n",
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" \n",
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" def newfunc(*args, auth_user, **kwargs):\n",
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" # newfunc now requires auth_user, and passes through all *other* parameters\n",
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" if auth_user in allowed_users:\n",
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" func(*args, **kwargs)\n",
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" else:\n",
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" print(\"ACCESS DENIED\")\n",
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" return newfunc\n",
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"\n",
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"# auth_user is no longer seen in the definition of these functions \n",
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"# but it can be passed in since the newfunc returned from auth_required accepts it\n",
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"@auth_required\n",
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"def withdraw_funds(account, amount):\n",
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" print(f\"withdrew {amount} funds from account={account}\")\n",
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"\n",
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"@auth_required\n",
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"def delete_account(account):\n",
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" print(\"deleted\", account)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 8,
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"id": "ee4cabe7",
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"withdrew 100 funds from account=jim\n"
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]
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}
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],
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"source": [
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"withdraw_funds(\"jim\", 100, auth_user=\"lauren\")"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 9,
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"id": "a22a86d9",
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"ACCESS DENIED\n"
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]
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}
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],
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"source": [
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"delete_account(\"kevin\", auth_user=\"jim\")"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "dca4b1ec",
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"metadata": {},
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"outputs": [],
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"source": []
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3 (ipykernel)",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.10.15"
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},
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"toc": {
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"base_numbering": 1,
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"nav_menu": {},
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"number_sections": false,
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"sideBar": true,
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"skip_h1_title": false,
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"title_cell": "Table of Contents",
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"title_sidebar": "Contents",
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"toc_cell": false,
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"toc_position": {},
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"toc_section_display": true,
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"toc_window_display": false
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}
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},
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"nbformat": 4,
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"nbformat_minor": 5
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}
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