Writing a class for books in Python

Question

I'm writing a class in Python that keeps track of a selection of books. There are three instance variables: author, title, and book_id. There are four methods:

1. __init__(self, author, title, book_id): (constructor; instantiates all instance variables.)
2. __str__(self): returns string representation with this format Book("Homer", "The Odyssey", 12345)
3. __repr__(self): returns same string representation as __str__
4. __eq__(self, other) determines if book itself is equivalent to the other book by checking if all three instance variables are the same. Returns a bool.

I've reached a road block. Here is the code I have so far I have gotten a good start. For some reason I keep getting indent errors with the return for the __repr__ method. If anyone familiar with writing classes has any advice I'd appreciate it.

class Book:
    def __init__(self, author, title, book_id):
        self.author = author
        self.title = title
        self.book_id = book_id

    def __str__(self):
        return 'Book(author, title, book_id)'

    def __repr__(self):

        return 'Book(author, title, book_id)'

    def __eq__(self, other):

    #Not sure if this is the right approach

        for title in Book:
            for title in Book:
                if title == title:
                    if author == author:
                        if book_id == book_id:
                            return True 

Answer 1

First, you are not implementing well the method __eq__. Second you are not, returning the data you have in your book, but just a string 'Book(author, title, book_id)'. I hope this solves your problem.

class Book:
    def __init__(self, author, title, book_id):
        self.author = author
        self.title = title
        self.book_id = book_id

    def __str__(self):
        return 'Book({}, {}, {})'.format(self.author, self.title, self.book_id)

    def __repr__(self):

        return 'Book({}, {}, {})'.format(self.author, self.title, self.book_id)

    def __eq__(self, other):
        return self.title == other.title and self.author == other.author and self.book_id == other.book_id