Add Item

Create a function named add_item that takes three arguments: item (string), price (float), and stock (int). The function should:

1. Check if the item already exists in the inventory dictionary.
   • If it does, print "Error: Item '<item>' already exists.".
2. If the item does not exist, add it to the inventory with the provided price and stock.
   • Store the price as a float and the stock as an integer.
3. Print "Item '<item>' added successfully.".

Add (replace) the following block of code at the bottom of your code:

add_item("Apple", 0.5, 100)
add_item("Banana", 0.2, 50)
add_item("Apple", 0.6, 30)  # Should print an error
print(inventory)