html5lib not thread safe. Is the Python SAX library thread-safe?

[Paul Rubin]

John Nagle <nagle at animats.com> writes:
>    But html5lib calls the XML SAX parser. Is that thread-safe?
> Or is there more trouble down at the bottom?

According to

  http://xmlbench.sourceforge.net/results/features200303/index.html

libxml and expat both purport to be thread-safe.  I've used the python
expat library (not from multiple threads) and it works fine, though the
python calls slow it down by worse than an order of magnitude.