code: def PublishableBox(publishable, box_type, nodelist, model=None):
      "add some content type info of self.target"
      if not model:
          model = publishable.content_type.model_class()
      box_class = model.box_class
  
      if box_class == PublishableBox:
          box_class = Box
      return box_class(publishable, box_type, nodelist, model=modelf PublishableBox(publishable, box_type, nodelist, model=None):
      "add some content type info of self.target"
      if not model:
          model = publishable.content_type.model_class()
      box_class = model.box_class
  
      if box_class == PublishableBox:
          box_class = Box
      return box_class(publishable, box_type, nodelist, model=model)
docs: add some content type info of self.target