code: def get_top_assets(self):
          
          imgs = self.articleimage_set.all()
          try:
              vids = self.videos.all()
          except AttributeError:
              # handles case where videos are not in installed apps
              # or otherwise unavailable
              vids = []
          return list(chain(imgs, vids))
docs: Returns chained list of top assets (photos and video) for commonized templates.