<div id="comment:0"></div> about negative comparison using "is not" CC: @tscrim @slel @kliem Component: **refactoring** Author: **Frédéric Chapoton** Branch/Commit: **[`c8499d1`](https://github.com/sagemath/sagetrac-mirror/commit/c8499d1a703a6f50e157a9270ff35b9a0a4772b7)** Reviewer: **Jonathan Kliem** _Issue created by migration from https://trac.sagemath.org/ticket/32758_