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+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Lab | Error Handling\n",
+    "\n",
+    "Completed version based on the customer-order functions from the previous labs."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": ["## 1. Initialize inventory with error handling"]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def initialize_inventory(products):\n",
+    "    inventory = {}\n",
+    "\n",
+    "    for product in products:\n",
+    "        while True:\n",
+    "            try:\n",
+    "                quantity = int(input(f\"Enter the quantity of {product}s available: \"))\n",
+    "                if quantity < 0:\n",
+    "                    raise ValueError(\"Quantity cannot be negative.\")\n",
+    "                inventory[product] = quantity\n",
+    "                break\n",
+    "            except ValueError as error:\n",
+    "                print(f\"Invalid input: {error} Please enter a non-negative whole number.\")\n",
+    "\n",
+    "    return inventory"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": ["## 2. Calculate total price with error handling"]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def calculate_total_price(customer_orders):\n",
+    "    total_price = 0\n",
+    "\n",
+    "    for product in customer_orders:\n",
+    "        while True:\n",
+    "            try:\n",
+    "                price = float(input(f\"Enter the price of {product}: \"))\n",
+    "                if price < 0:\n",
+    "                    raise ValueError(\"Price cannot be negative.\")\n",
+    "                total_price += price\n",
+    "                break\n",
+    "            except ValueError as error:\n",
+    "                print(f\"Invalid input: {error} Please enter a non-negative number.\")\n",
+    "\n",
+    "    return total_price"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": ["## 3. Get customer orders with error handling"]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def get_customer_orders(inventory):\n",
+    "    while True:\n",
+    "        try:\n",
+    "            num_orders = int(input(\"Enter the number of customer orders: \"))\n",
+    "            if num_orders < 0:\n",
+    "                raise ValueError(\"The number of orders cannot be negative.\")\n",
+    "            break\n",
+    "        except ValueError as error:\n",
+    "            print(f\"Invalid input: {error} Please enter a non-negative whole number.\")\n",
+    "\n",
+    "    customer_orders = []\n",
+    "\n",
+    "    for _ in range(num_orders):\n",
+    "        while True:\n",
+    "            try:\n",
+    "                product = input(\"Enter the product name: \").strip().lower()\n",
+    "                if product not in inventory:\n",
+    "                    raise ValueError(\"This product is not in the inventory.\")\n",
+    "                if inventory[product] <= 0:\n",
+    "                    raise ValueError(\"This product is out of stock.\")\n",
+    "                if customer_orders.count(product) >= inventory[product]:\n",
+    "                    raise ValueError(\"There is not enough stock for another order of this product.\")\n",
+    "                customer_orders.append(product)\n",
+    "                break\n",
+    "            except ValueError as error:\n",
+    "                print(f\"Invalid product: {error} Available products: \"\n",
+    "                      f\"{[name for name, stock in inventory.items() if stock > 0]}\")\n",
+    "\n",
+    "    return customer_orders"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": ["## Supporting functions and complete program"]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def update_inventory(inventory, customer_orders):\n",
+    "    for product in customer_orders:\n",
+    "        inventory[product] -= 1\n",
+    "    return {product: quantity for product, quantity in inventory.items() if quantity > 0}\n",
+    "\n",
+    "\n",
+    "def print_updated_inventory(inventory):\n",
+    "    print(\"Updated Inventory:\")\n",
+    "    for product, quantity in inventory.items():\n",
+    "        print(f\"{product}: {quantity}\")\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    products = [\"t-shirt\", \"mug\", \"hat\", \"book\", \"keychain\"]\n",
+    "    inventory = initialize_inventory(products)\n",
+    "    customer_orders = get_customer_orders(inventory)\n",
+    "    total_price = calculate_total_price(customer_orders)\n",
+    "    inventory = update_inventory(inventory, customer_orders)\n",
+    "\n",
+    "    print(f\"\\nTotal products ordered: {len(customer_orders)}\")\n",
+    "    print(f\"Total price: {total_price:.2f}\")\n",
+    "    print_updated_inventory(inventory)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## 4. Manual test\n",
+    "\n",
+    "Run the cell below and deliberately try:\n",
+    "- text and a negative number for inventory quantity;\n",
+    "- text and a negative number for the number of orders;\n",
+    "- an unknown product, an out-of-stock product and more orders than available stock;\n",
+    "- text and a negative price.\n",
+    "\n",
+    "The program should display an error and ask again instead of stopping."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": ["main()"]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {"display_name": "Python 3", "language": "python", "name": "python3"},
+  "language_info": {"name": "python", "version": "3"}
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}