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 Object-Oriented Python Advanced Objects Frustration

Tobiasz Lorenc
Tobiasz Lorenc
3,757 Points

__len__ problem, help me

Now I want you to make a subclass of list. Name it Liar.

Override the len method so that it always returns the wrong number of items in the list. For example, if a list has 5 members, the Liar class might say it has 8 or 2.

You'll probably need super() for this.

frustration.py
import random

class Liar(list):
    def __len__(self, other):
        super().__len__(self,other)
        return self# + bool(random.randint(-2, 2))

Bot answer: Bummer: TypeError: len() missing 1 required positional argument: 'other'

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 67,778 Points

You are on the right track.

  • the __len__ method doesn’t take arguments so only self is needed on the def line, and no arguments are needed in the super call.
  • the results of the super call are not saved
  • modify the results from super call and return it.

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