Let's Encrypt证书生成失败

在使用Let's Encrypt时出现下面了的情况，想知道有没有什么解决办法：

Traceback (most recent call last):
 File "/usr/local/python/bin/certbot", line 11, in <module>
 sys.exit(main())
 File "/usr/local/python/lib/python2.7/site-packages/certbot/main.py", line 729, in main
 args = cli.prepare_and_parse_args(plugins, cli_args)
 File "/usr/local/python/lib/python2.7/site-packages/certbot/cli.py", line 1089, in prepare_and_parse_args
 helpful.add_deprecated_argument("--agree-dev-preview", 0)
 File "/usr/local/python/lib/python2.7/site-packages/certbot/cli.py", line 741, in add_deprecated_argument
 self.parser.add_argument, argument_name, num_args)
 File "/usr/local/python/lib/python2.7/site-packages/certbot/util.py", line 479, in add_deprecated_argument
 configargparse.ACTION_TYPES_THAT_DONT_NEED_A_VALUE.add(ShowWarning)
AttributeError: 'tuple' object has no attribute 'add'