docs: def handle_wiki(msg):
      """ Given a wiki message, return the FAS username. """
  
      if 'wiki.article.edit' in msg.topic:
          username = msg.msg['user']
      elif 'wiki.upload.complete' in msg.topic:
          username = msg.msg['user_text']
      else:
          raise ValueError("Unhandled topic.")
  
      return username