QVariantAnimation doesn't trigger signals

class AreaScene(QGraphicsScene):
    def __init__(self, parent = None):
         super().__init__()
         self.addItem(QGraphicsRectItem(0,0,10,10))
         self.anim = QVariantAnimation()
         self.anim.setDuration(1000)
         self.anim.setStartValue(1)
         self.anim.setEndValue(10)
         self.anim.valueChanged.connect(self.test) 
         self.anim.start()
    def test(self, x):
        print("hello")