Merge pull request #19614 from meeseeksmachine/auto-backport-of-pr-19597-on-v3.4.x

QuLogic · web-flow · commit 3c112892fed1 · 2021-03-01T23:30:57.000-05:00
Backport PR #19597 on branch v3.4.x (Fix IPython import issue)
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1743,7 +1743,7 @@ def _fix_ipython_backend2gui(cls):
         # `ipython --auto`).  This cannot be done at import time due to
         # ordering issues, so we do it when creating a canvas, and should only
         # be done once per class (hence the `lru_cache(1)`).
-        if "IPython" not in sys.modules:
+        if sys.modules.get("IPython") is None:
             return
         import IPython
         ip = IPython.get_ipython()
