I haven't had a chance to try the patch (underpth_blank_lines.diff) or apply it, but it looks right.

If one of the other core devs gets to apply this before I do, feel free.

Alexey, you don't need to sign a CLA for this fix, but if you're going to contribute more then you may want to: https://docs.python.org/devguide/committing.html#contributor-licensing-agreements It's all online, and it'll help save the core developers from having to evaluate whether you need it or not (which I can do, because it comes up often for me in my day job, but not everyone has that experience). And thanks for this patch!