def bringChildToFront(self, child):
    'Bring it to the top layer.'
    try:
        self.zOrder.remove(child)
    except ValueError:
        pass
    self.zOrder.append(child)
Bring it to the top layer.
def bringChildToFront(self, child):
    
    try:
        self.zOrder.remove(child)
    except ValueError:
        pass
    self.zOrder.append(child)