For this recipe, we will use the code from the previous recipe. As an example, we will increase the existing book price by $10 USD. Note that you might using another currency based on company configurations.

Follow these steps to invoke the Python method from the XML file:

1. Add the _update_book_price() method in the library.book model:

@api.model
def _update_book_price(self):
    all_books = self.search([])
    for book in all_books:
        book.cost_price += 10

2. Add <function> in the data XML file:

<function model="library.book" name="_update_book_price"/>