[docs] [issue18301] In itertools.chain.from_iterable() there is no cls argument

[Serhiy Storchaka]

Changes by Serhiy Storchaka <storchaka at gmail.com>:


----------
assignee: serhiy.storchaka -> rhettinger

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue18301>
_______________________________________