code: def _update_clipper(self):
          
          if self.clip_children and self._clipper is None:
              self._clipper = Clipper()
          elif not self.clip_children:
              self._clipper = None
  
          if self._clipper is None:
              return
          self._clipper.rect = self.inner_rect
          self._clipper.transform = self.get_transform('framebuffer', 'visual')
docs: Called whenever the clipper for this widget may need to be updated.