Apply Publisher Promotions to Book Prices

Problem

An online bookstore runs promotions by publisher. Two DataFrames are loaded from CSV: `books` (`book_id`, `publisher`, `list_price`) where list_price is in whole shekels, and `promotions` (`publisher`, `percentage_off`) giving a discount percentage for some publishers.

Compute the `checkout_price` for every book as list_price minus list_price * percentage_off / 100, using integer (floor) division to match the SQL twin. Books whose publisher has no promotion keep their list_price unchanged. Return a DataFrame with columns `book_id`, `checkout_price`, `publisher`, ordered by `book_id`.

Input data

Example rows — the live problem includes the full dataset.

Expected output

Your answer should return 4 rows with the columns book_id, checkout_price, publisher.

Starter code (Pandas (Python))

import pandas as pd

def checkout_prices(books, promotions) -> pd.DataFrame:
    # Your code here
    return books

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