[docs] [issue17902] Document that _elementtree C API cannot use custom TreeBuilder for iterparse or IncrementalParser

Eli Bendersky added the comment: Aaron, could you please sign the PSF CLA (http://www.python.org/psf/contrib/contrib-form/) - this will make it accepting patches from you easier. Other than that, I agree it's a legit patch. The alternative would be to fix _elementtree to actually allow arbitrary TreeBuilders there, although I'm not sure it's worth the effort. ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue17902> _______________________________________