On Wed, Jan 30, 2013 at 11:36 PM, Zhongyue Luo <zhongyue.nah at intel.com> wrote: > What I'm suggesting is that we should add an entry in HACKING.rst stating we > should use "if X not in Y" and prevent mix use of the two. > > Would there be any reason why we shouldn't do this? such as it adds more > burden to reviewers, or because we should have the freedom to choose > whatever we want to use? +1 for adding it to the guidelines. The "not in" expression is the correct way to test for collection membership (http://docs.python.org/2.7/reference/expressions.html#not-in). Happy Hacking! 7-11