Icon Request

• Icon name: folder-open
• Use case: Tree views usually need a way to show that an item has sub-items and whether or not an item is open. The "folder" icon is good for showing the existence of child items. When that list is opened, it'd be nice to have a "folder-open" icon to show the state. "folder-open" has many more use-cases but this is my specific use-case.
• Screenshots of similar icons: