Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

Python Basic Object-Oriented Python Emulating Built-ins Emulating Built-ins

def __str__(self):: return f`{self.author} {self.title}` what's wrong with the syntax?

I followed the syntax from the video exactly, why do i get invalid syntax?

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

    def __str__(self)::
            return f`{self.author} {self.title}`
from book import Book

class BookCase:
    def __init__(self):
       self.books = []

    def add_books(self, book):

1 Answer

Chris Freeman
Chris Freeman
Treehouse Moderator 67,778 Points

Hey jack twist, it looks like your quotation marks are “backticks” and not single quote marks. You have ` when you need ‘

Post back if you need more help. Good luck!!!

Hey Chris, thanks for your answer! I changed the my code to

 <--    def __str__(self):
            return f'{self.author} {self.title}'   -->

but it still doesn't pass:

Traceback (most recent call last):
  File "", line 64, in test_results
AssertionError: 'John Green Paper Towns' != 'John Green, Paper Towns'
- John Green Paper Towns
+ John Green, Paper Towns
?           +
 : Hmm...when I input John Green, Paper Towns
Chris Freeman
Chris Freeman
Treehouse Moderator 67,778 Points

Sorry two errors left:

  • colon should be single : not doubled ::
  • a comma is missing from the formatted string after the author name