OK, a few things:

A. I would make head and size private, you don't want them changed from outside the class.

B. You should use __len__ instead of __sizeof__ - they have different meanings.

C. Implement __iter__

D. After doing C, Format the repr using: "[{}]". format(", ". join(map(str, self)))

OK, a few things:

1. I would make head and size private, you don't want them changed from outside the class.

2. You should use __len__ instead of __sizeof__ - they have different meanings.

3. Implement __iter__

4. After doing #3, format the repr using:

   "[{}]". format(", ". join(map(str, self)))