Martin von Zweigbergk <martinvonz@google.com> [Thu, 05 Dec 2019 08:59:23 -0800] rev 43795
exchange: replace a "not x in ys" by more Pythonic "x not in ys"
Found by one of our (Google-)internal tools.
Differential Revision: https://phab.mercurial-scm.org/D7546