How to correct the code in fastai?

Recently I watch the video in the course of fastai. I find it’s convenient to me . But I am in trouble in the first day . I think errors may occur in regular expressions . How to correct it?

any help would be greatly appreciated

Could you post the error message?
I’m not familiar with the fastai code, but it looks like the regex is used to get (some part of) the path before the image number.
Could you also post a link to the lesson or code?