ipympl changes MPL backend on import

• xref: https://github.com/mne-tools/mne-python/pull/13963#pullrequestreview-4499976618

In mne-python (see above), we have a functionality called sys_info, which gives us (among other things) the versions of all sorts of installed packages.

For this reason, we also import ipympl.

At import time, ipympl actually changes the MPL backend.

Is this something that could be avoided? This change in backend was very surprising to us and it took an in-depth profiling to identify it as the cause of a massive memory leak in a pipeline that produced several plots on each iteration, never closing them due to the backend change.

Examinez le comportement lors de l’import décrit dans l’issue et dans la revue de la pull request mne-python liée, en vous concentrant sur l’endroit où l’importation de ipympl modifie le backend de Matplotlib. Reproduisez cela avec la séquence d’importation de type sys_info et vérifiez que l’importation de ipympl ne modifie plus le backend et ne provoque pas le problème de cycle de vie des graphiques signalé.