code: def get_channel_node_from_json(json_tree):
      
      channel = ChannelNode(
          title=json_tree['title'],
          description=json_tree['description'],
          source_domain=json_tree['source_domain'],
          source_id=json_tree['source_id'],
          language=json_tree['language'],
          thumbnail=json_tree.get('thumbnail', None),
      )
      return channel
docs: Build `ChannelNode` from json data provided in `json_tree`.