Flat QTreeView items - not nested

Does anyone know if it's possible the flatten a QTreeView/QTreeWidget while still being able to expand child items. What the default is: ``` - A -> A1 -> A2 - B -> B2 + C ``` `-` is expanded and `+` is collapsed What I would like: ``` - A A1 A2 - B B2 + C ``` all collapsed ``` + A + B + C ``` `A, B, C` are the root items.