Fixed example to work with CP 4 and fixed index out of range error

Author: Melissa LeBlanc-Williams

adafruit_button.py

@@ -146,7 +146,7 @@ def label(self):
 
     @label.setter
     def label(self, newtext):
-        if self._label and (self.group[-1] == self._label):
+        if self._label and len(self.group) > 0 and (self.group[-1] == self._label):
             self.group.pop()
 
         self._label = None

examples/display_button_simpletest.py

@@ -37,8 +37,8 @@
 color_palette[0] = 0x404040
 bg_sprite = displayio.TileGrid(color_bitmap,
                                pixel_shader=color_palette,
-                               position=(0, 0))
-print(bg_sprite.position)
+                               x=0, y=0)
+print(bg_sprite.x, bg_sprite.y)
 splash.append(bg_sprite)
 
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