add comment to protect against future 'cleanup' of if ret is False

minrk · minrk · commit 2ac78c777396 · 2012-11-13T12:11:58.000-08:00
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1123,6 +1123,8 @@ def _on_timer(self):
         '''
         for func, args, kwargs in self.callbacks:
             ret = func(*args, **kwargs)
+            # docstring above explains why we use `if ret is False` here,
+            # instead of `if not ret`.
             if ret is False:
                 self.callbacks.remove((func, args, kwargs))
 
