It's a mistake to filter out whitespace changes on Python diffs. These days it's best use `Black --check` or similar in CI to make sure they've matched your whitespace settings, to minimise these changes.
I am working on a GitHub pull request viewer that displays changes using a semantic diff, and therefore has some more advanced whitespace handling behavior than just ignoring leading or trailing whitespace. I tried it with this PR:
It doesn't make a huge difference, but it filters out changes like the added line break in "if value: value = str(value)" nicely. I haven't announced the project yet, but maybe someone will find it useful :-)
Also, Git had it since forever, and since GitHub's diff view isn't particularly convenient for browsing multi-commit PRs you usually review the changes using Git anyway.
That said, I'd ask the contributor to tidy up the branch first. It's kinda disrespecting to ask others to review branches in such state.