Haonan Chen

See page 59 of the [textbook](http://incompleteideas.net/book/bookdraft2018jan1.pdf).

What's the full traceback?

Looks like you are using python 2. You can try to change `TemporaryDirectory ` to `tempdir`: https://docs.python.org/2/library/tempfile.html

Seems like you already have a checkpoint? Maybe clean up you directory and run again. (If that not the case, please provide the full error message.)

Ok, I think the rule is if the word ends with 'ice' then the singularization is to change it to 'ouse'. But 'slice' is apparently an exception.

Another case: `singularize('pasta') == 'pastum'`

Are you running the example or your own ppt?