Merge pull request matplotlib#5514 from fariza/string-format-example

adding str to force string in format

Author: WeatherGod

examples/user_interfaces/toolmanager.py

@@ -41,7 +41,7 @@ def trigger(self, *args, **kwargs):
         print("{0:12} {1:45}".format("Group", "Active"))
         print('-' * 80)
         for group, active in self.toolmanager.active_toggle.items():
-            print("{0:12} {1:45}".format(group, active))
+            print("{0:12} {1:45}".format(str(group), str(active)))
 
 
 class GroupHideTool(ToolToggleBase):