class Book:
    def __init__(self, author, title):
        self.author = author
        self.title = title
    def display(self):
        print(self.title + ', written by ' + self.author)

a = Book('John Steinbeck', 'Of Mice and Men')
b = Book('Harper Lee', 'To Kill a Mockingbird')
a.display()
b.display()
