Setting style on QTreeWidget root items (PyQT)

[jspeirs]

Is there a way to set a style for only the root items in a QTreeWidget?

For example if below is my tree, I'd like to set a style on just the "/bob" and "/tom" items.

/bob
     /photos
     /documents
/tom
    /photos
    /documents

I tried this and a few other variations with no luck:

TREE_STYLESHEET = """
    QTreeView::item:first  {
        background-color: red;
    }
"""
self.MyTreeWidget.setStyleSheet(TREE_STYLESHEET)

I've been looking here:

http://doc.qt.io/qt-5/stylesheet-reference.html