How do you scale a pen so that the pen width appears constant when the view is scaled

Here's my QGraphicsView code:

Code:

def wheelEvent(self, event):
        if QApplication.keyboardModifiers() & (Qt.ControlModifier | Qt.ShiftModifier):
            self.setTransformationAnchor(self.AnchorUnderMouse)
            #Scale the view / do the zoom
            scaleFactor = 1.08   
 
            if event.angleDelta().y() > 0:
                #Zoom in
                self.scale(scaleFactor, scaleFactor)
            else:
                self.scale(1.0/scaleFactor, 1.0/scaleFactor)
 
    #Assumes scaleX = scaleY
    def scale(self, scaleX, scaleY):
        self.scene().viewScale(scaleX)
        QGraphicsView.scale(self, scaleX, scaleY)

viewScale() of scene() in turn calls viewScale of SnapGridGraphicsItem:

Code:

def viewScale(self, scale):
        #self.pen.setWidth(1.0 / scale)
        self.pen = QPen(self.color, 1.0 / scale)

I've also tried multiplying 1.0 / scale x pen.width() and the same result happens: nothing - lines are still scaled with zoom action. Please help! :|

I also already have ItemIgnoresGeometricTransformations enabled for SnapGridGraphicsItem...