'Sets the depth value of this item. Default is 0.
This controls the order in which items are drawn--those with a greater depth value will be drawn later.
Items with negative depth values are drawn before their parent.
(This is analogous to QGraphicsItem.zValue)
The depthValue does NOT affect the position of the item or the values it imparts to the GL depth buffer.'

def setDepthValue(self, value):

    self.__depthValue = value
