diff --git a/examples/guide/firstwidget/6_button.py b/examples/guide/firstwidget/6_button.py
index 667aed5e7..428a6bb00 100644
--- a/examples/guide/firstwidget/6_button.py
+++ b/examples/guide/firstwidget/6_button.py
@@ -23,17 +23,16 @@ class MyPaintApp(App):
 
     def build(self):
         parent = Widget()
-        painter = MyPaintWidget()
+        self.painter = MyPaintWidget()
         clearbtn = Button(text='Clear')
-        parent.add_widget(painter)
+        clearbtn.bind(on_release=self.clear_canvas)
+        parent.add_widget(self.painter)
         parent.add_widget(clearbtn)
-
-        def clear_canvas(obj):
-            painter.canvas.clear()
-        clearbtn.bind(on_release=clear_canvas)
-
         return parent
 
+    def clear_canvas(self, obj):
+        self.painter.canvas.clear()
+
 
 if __name__ == '__main__':
     MyPaintApp().run()