code: def sync_state(self):
          
          oradius = self.radius + self.width
          if oradius < self.radius:
              raise ValueError('Outer boundary < inner boundary')
  
          d = dict(points=self.points, radius=self.radius, color=self.color,
                   linewidth=self.linewidth, linestyle=self.linestyle,
                   alpha=self.alpha)
  
          # update inner object
          self.objects[0].__dict__.update(d)
  
          # update outer object
          d['radius'] = oradius
          self.objects[1].__dict__.update(d)
docs: Called to synchronize state (e.g. when parameters have changed).