code: def construct_channel(self, **kwargs):
          
          channel = self.get_channel(**kwargs)
          json_tree_path = self.get_json_tree_path(**kwargs)
          json_tree = read_tree_from_json(json_tree_path)
          build_tree_from_json(channel, json_tree['children'])
          raise_for_invalid_channel(channel)
          return channel
docs: Build the channel tree by adding TopicNodes and ContentNode children.