Changelog:
=============
- Fix a crash when parsing an empty arbitrary expression with extract_node (extract_node("__()")).
- Fix a crash when parsing a slice called in a decorator on a function that is
also decorated with a known six decorator.
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
