nltk - python ntlk donwload gives parser eror -

i trying run following command

import nltk nltk.download('all') 

but getting error

traceback (most recent call last):   file "./update.py", line 3, in <module>     nltk.download('all')   file "/usr/lib/python3.6/site-packages/nltk/downloader.py", line 664, in download     msg in self.incr_download(info_or_id, download_dir, force):   file "/usr/lib/python3.6/site-packages/nltk/downloader.py", line 534, in incr_download     try: info = self._info_or_id(info_or_id)   file "/usr/lib/python3.6/site-packages/nltk/downloader.py", line 508, in _info_or_id     return self.info(info_or_id)   file "/usr/lib/python3.6/site-packages/nltk/downloader.py", line 875, in info     self._update_index()   file "/usr/lib/python3.6/site-packages/nltk/downloader.py", line 825, in _update_index     elementtree.parse(compat.urlopen(self._url)).getroot())   file "/usr/lib/python3.6/xml/etree/elementtree.py", line 1196, in parse     tree.parse(source, parser)   file "/usr/lib/python3.6/xml/etree/elementtree.py", line 597, in parse     self._root = parser._parse_whole(source) xml.etree.elementtree.parseerror: not well-formed (invalid token): line 23, column 143 

i new python, not sure should do. looked source module reported above , noticed trying download xml file. ran below command , did not give me error.

compat.urlopen('https://raw.githubusercontent.com/nltk/nltk_data/gh-pages/index.xml') 

so presume there no issue in download, in parser. can suggest how proceed here?

index.xml had typo. patched. checked , nltk.download('all') works fine!

see: nltk/nltk_data#70