设置树形目录由展开到闭合的图标
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## Icon Request

* Icon name:   close tree
* Tags of this icon: 
* Use case: 设置树形目录由展开到闭合的图标
* Screenshots of similar icons:设置树形目录由展开到闭合的图标
![IMG_20200808_112219](https://user-images.githubusercontent.com/31270164/89701544-8f2be200-d96a-11ea-9faa-2e0424e5dc2f.jpg)
