UnboundLocalError: cannot access local variable 'post' where it is not associated with a value #3504

NotFound: 404 Not Found (error code: 10003): Unknown Channel
  File "bot/exts/help_channels/_channel.py", line 196, in maybe_archive_idle_post
    post = await get_or_fetch_channel(bot.instance, post_id)

UnboundLocalError: cannot access local variable 'post' where it is not associated with a value
  File "bot/exts/help_channels/_channel.py", line 198, in maybe_archive_idle_post
    log.trace(f"Not closing missing post #{post} ({post.id}).")