code: def action_download(self, courseid, taskid, path):
          
  
          wanted_path = self.verify_path(courseid, taskid, path)
          if wanted_path is None:
              raise web.notfound()
  
          task_fs = self.task_factory.get_task_fs(courseid, taskid)
          (method, mimetype_or_none, file_or_url) = task_fs.distribute(wanted_path)
  
          if method == "local":
              web.header('Content-Type', mimetype_or_none)
              return file_or_url
          elif method == "url":
              raise web.redirect(file_or_url)
          else:
              raise web.notfound()
docs: Download a file or a directory