diff --git a/lab-python-error-handling.ipynb b/lab-python-error-handling.ipynb
index f4c6ef6..6c24371 100644
--- a/lab-python-error-handling.ipynb
+++ b/lab-python-error-handling.ipynb
@@ -72,11 +72,97 @@
     "\n",
     "4. Test your code by running the program and deliberately entering invalid quantities and product names. Make sure the error handling mechanism works as expected.\n"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "8f511565",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def initialize_inventory(products): \n",
+    "    inventory = {}\n",
+    "    for product in products:\n",
+    "        valid_quantity = False \n",
+    "        while not valid_quantity: #Le programme revient ensuite au début de la boucle  while  et demande à l'utilisateur de saisir un nouveau nombre.\n",
+    "            try: # Par exemple, si on demande à l'utilisateur de saisir un nombre, mais qu'il saisit un texte au lieu d'un nombre, cela peut causer une erreur. Pour éviter cela, on peut utiliser un bloc  try/except  pour gérer l'erreur, et afficher un message d'erreur personnalisé à l'utilisateur. # le bloc  try  contient le code qui peut causer une erreur, c'est-à-dire la conversion de la saisie utilisateur en un entier.\n",
+    "                quantity = int(input(f\"Enter the quantity of {product}s available: \"))\n",
+    "                if quantity < 0:\n",
+    "                    raise ValueError(\"Invalid quantity! Please enter a non-negative value.\")\n",
+    "                valid_quantity = True\n",
+    "            except ValueError as error: #Si une erreur se produit, le bloc  except  est exécuté et affiche un message d'erreur personnalisé. \n",
+    "                print(f\"Error: {error}\")\n",
+    "        inventory[product] = quantity\n",
+    "    return inventory #Le programme revient ensuite au début de la boucle  while  et demande à l'utilisateur de saisir un nouveau nombre.\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "0ff91b22",
+   "metadata": {},
+   "source": [
+    "#( replace “inventory” with price) #calculate_total_price"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "fe2af297",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def calculate_total_price(products): \n",
+    "    price = {}\n",
+    "    for product in products:\n",
+    "        valid_price = False \n",
+    "        while not valid_price: #The program then returns to the beginning of the `while` loop and prompts the user to enter a new number.\n",
+    "            try: # The  try  block contains the code that may cause an error, namely converting the user input to an integer.\n",
+    "                price = float(input(f\"Enter the price of {product}s available: \"))\n",
+    "                if price < 0:\n",
+    "                    raise ValueError(\"Invalid price! Please enter a non-negative value.\") \n",
+    "                valid_price = True\n",
+    "            except ValueError as error: #If an error occurs, the `except` block is executed and displays a custom error message. \n",
+    "                print(f\"Error: {error}\")\n",
+    "        inventory[product] = price\n",
+    "    return price #The program then returns to the beginning of the `while` loop and prompts the user to enter a new number."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "fec3430a",
+   "metadata": {},
+   "source": [
+    "#( replace “inventory” with orders) #get_customer_orders"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "6044594b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def get_customer_orders(products): \n",
+    "    orders = {}\n",
+    "    for product in products:\n",
+    "        valid_orders = False \n",
+    "        while not valid_orders: #The program then returns to the beginning of the `while` loop and prompts the user to enter a new number.\n",
+    "            try: # The  try  block contains the code that may cause an error, namely converting the user input to an integer.\n",
+    "                orders = int(input(f\"Enter the quantity of {product}s available: \"))\n",
+    "                if orders < 0:\n",
+    "                    raise ValueError(\"Invalid orders! Please enter a non-negative value.\")\n",
+    "                valid_orders = True\n",
+    "            except ValueError as error:  #If an error occurs, the `except` block is executed and displays a custom error message. \n",
+    "                print(f\"Error: {error}\")\n",
+    "        orders[product] = orders\n",
+    "    return orders  #The program then returns to the beginning of the `while` loop and prompts the user to enter a new number."
+   ]
   }
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3 (ipykernel)",
+   "display_name": "base",
    "language": "python",
    "name": "python3"
   },
@@ -90,7 +176,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.13"
+   "version": "3.12.4"
   }
  },
  "nbformat": 4,