Instance methods are simply functions written inside of a class, but they always have their first parameter named self. The self parameter represents the same thing as this in Java, and it is set by Python—the caller does not write a corresponding argument inside the call's parentheses. For example:

class Book(object):
    def print_info(self, comment):
        print(self)
        print(comment)

creates a method that takes one argument, a comment, and prints the book followed by the comment. It could be called like this:

book = Book()
book.print_info('(400 pages)')

Fill in the placeholders so that the actual outputs match the expected outputs.