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

    def __eq__(self, other: object) -> bool:
        return self.title == other.title and self.author == other.author
    
    def __hash__(self) -> int:
        return hash((self.title, self.author))
    

already_read = set()
already_read.add(Book("1984", "George Orwell"))
book = Book("1984", "George Orwell")
book2 = Book("1984", "George Orwell")
already_read.add(book2)

print(book in already_read)
print(already_read)
print(book == book2)
print(book is book2)


# already_read2 = set()
# already_read2.add("1984")
# book = "1984"
# print(book in already_read2)