The warehouse wants a label for each product's stock.

1. Create stock_label(p_id integer), which returns text. Read the stock of product p_id into a variable, then return:
   • sold out when the stock is 0,
   • low when it is below 10,
   • ok otherwise.
2. List every product's name and its label, in that order.
3. Replace the function so that it also sends a notice with the product id and the stock it read. Keep the labels the same.
4. Run SELECT stock_label(12); and read the notice.