Backport PR #17720: Fix check for manager = None.

QuLogic · meeseeksmachine · commit 6aaa675e4b0d · 2020-06-22T19:51:25.000Z
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -2233,15 +2233,15 @@ def get_window_title(self):
         Return the title text of the window containing the figure, or None
         if there is no window (e.g., a PS backend).
         """
-        if self.manager:
+        if self.manager is not None:
             return self.manager.get_window_title()
 
     def set_window_title(self, title):
         """
         Set the title text of the window containing the figure.  Note that
         this has no effect if there is no window (e.g., a PS backend).
         """
-        if hasattr(self, "manager"):
+        if self.manager is not None:
             self.manager.set_window_title(title)
 
     def get_default_filename(self):
