PyQT customizing specific ScrollBar

Question

I would like to apply different colors to my scrollbars depending on their parent QListView, and I would like to do this from "higher level" than the QListView

Question is, how to apply different styles to scrollbars in a stylesheet? For example, for a QPushButton, I'll use QPushButton#<name>, but what should I do for QScrollBar selector?

EDIT

You can find a code sample in the question of this topic. As shown in the linked image, the scrollbar are NOT styled accordingly to their stylesheet (no color, border)