Fix example code for enabling logging in API change notice (#18094)

dopplershift · timhoffm · web-flow · commit 11d5b75ea783 · 2020-07-29T00:45:01.000+02:00
* MNT: Fix example code to enable logging.

`set_level` doesn't exist, and nothing appears without a handler.

* Add comment about addHandler

Co-authored-by: Tim Hoffmann &lt;2836374+timhoffm@users.noreply.github.com&gt;

Co-authored-by: Tim Hoffmann &lt;2836374+timhoffm@users.noreply.github.com&gt;
diff --git a/doc/api/prev_api_changes/api_changes_3.1.0.rst b/doc/api/prev_api_changes/api_changes_3.1.0.rst
@@ -531,7 +531,11 @@ The following miscellaneous API elements have been removed
 
     import logging
     logger = logging.getLogger('matplotlib')
-    logger.set_level(logging.INFO)
+    logger.setLevel(logging.INFO)
+    # configure log handling: Either include it into your ``logging`` hierarchy,
+    # e.g. by configuring a root looger using ``logging.basicConfig()``,
+    # or add a standalone handler to the matplotlib logger:
+    logger.addHandler(logging.StreamHandler())
 
 - ``__version__numpy__``
 - ``collections.CIRCLE_AREA_FACTOR``
