code: def create_widget(self):
          
          d = self.declaration
  
          if self.indeterminate:
              #: Note: Style will only exist on activity indicators!
              style = ProgressBar.STYLES[d.size]
          else:
              style = ProgressBar.STYLE_HORIZONTAL
          self.widget = ProgressBar(self.get_context(), None, style)
docs: Create the underlying widget.