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0. Report Issue Guide

1. Please run the following command and check whether the problem has been fixed：

rm -rf package-lock.json
rm -rf node_modules
npm install

2. Please search in FAQ List first, and make sure your problem has not been solved before.

3. Please search in the issue first, and make sure your problem had not been reported before

1. Versions

• What is your wechaty version?
  Answer: v0.29.32

• Which puppet are you using for wechaty? (padchat/puppeteer/padpro/...)
  Answer: wechaty-puppet-padplus

• What is your wechaty-puppet-XXX（padchat/puppeteer/） version?
  Answer: v0.3.2

• What is your node version? (run node --version)
  Answer: v10.17.0

• What os are you using
  Answer: mac 10.12.6

2. Describe the bug

我想要设置群公告为空，但是当传入空字符串的时候，仅仅是获取群公告，而不是设置群公告为空

3. To Reproduce

Steps to reproduce the behavior:

1. run '...'
2. ...
3. ...

4. Expected behavior

我希望有个一个专门的参数类型，用来处理清空群公告。对空字符也能进行一些处理。

5. Actual behavior

If applicable, add screenshots to help explain your problem. But do not paste log screenshots here.

6. Full Output Logs

Set env WECHATY_LOG=silly in order to set log level to silly, then we can get the full log (If you dosen't set log env, log level is info as default, we cannot get the full log)

We need full log instead of log screenshot or log fragments!

$ WECHATY_LOG=silly node yourbot.js

Question: Paste your FULL(DO NOT ONLY PROVIDE FRAGMENTS) log messages
Answer:

7. Additional context

Add any other context about the problem here.

[bug]