Implement a Book and Author Composition

Summary

Model books composed of authors and implement methods to manage and query author relationships.

Problem statement

You will create two classes: Author and Book. An Author stores basic information (name, birth year, optional bio). A Book is composed of one or more Authors and stores metadata (title, publication year, pages). Implement methods to manage the composition and to query relationships between a book and its authors. Required features: - Author: initialize with name, optional birth_year and bio. Implement readable string representation and equality comparison (authors are equal if name and birth_year match). - Book: initialize with title, optional list of Author objects, publication year, and pages. - Book.add_author(author): add an Author instance, avoiding duplicates. - Book.remove_author(name_or_author): remove an author by name (string) or by Author instance; if not present, do nothing. - Book.author_names(): return list of author names in order. - Book.co_authors(author_name): given the name of one author, return a list of the other authors' names (order preserved). If the author isn't on the book, return an empty list. - Book.is_by_author(author_name): returns True if the author is one of the book's authors. Design the classes to be easy to use in composition: a Book contains Author objects (not just strings). Keep behavior predictable for duplicate additions and removals.

Task

Use composition to model Book and Author classes, implement methods to add/remove authors, query co-authors and check authorship.

Examples

Input format

You will construct Author and Book objects and call methods on the Book instance. Each test is a single Python expression that returns a value.

Output format

Return values depend on the method: lists of strings for author lists, booleans for checks. The test harness compares str(value).

Constraints

- Do not use any external libraries. - Treat authors as equal when both name and birth_year match. - Methods should not print; they should return values. - Preserve author ordering unless an author is removed. - Avoid duplicate authors in a Book.

Samples