pyserial: read_all cannot return None?

[rtandy]

The pyserial documentation says that read returns bytes. The comment in serialutil.pyi discusses this and has read and read_until returning bytes, not bytes | None.

For some reason read_all is typed as returning bytes | None? The implementation simply calls read, so I don't see why it's different from read.

Have I missed something?

Thanks for maintaining typeshed!

[srittau]

This looks like a simple oversight to me. Fix welcome!