At first that's what I assumed you meant by "whitespace" (that it was indentation), but re-reading I thought you meant it included things like spaces (i.e. two spaces after an assignment operator, etc.).

It's been a good number of years since I've used Python, so I can't remember which it is. Another programming language that parses based on indentation is fresher in my mind, so that's what I went with initially. When I looked at your post again, that's when I realized that whitespace isn't always tabs.