code: def _all_shorten(self):
          
          # Toggle all shortened URLs
          self.shorten = not self.shorten
          urls = iter(self.urls)
          for item in self.items:
              # Each Column has (Text, Button). Update the Button label
              if isinstance(item, urwid.Columns):
                  item[1].set_label(shorten_url(next(urls),
                                                self.size[0],
                                                self.shorten))
docs: S