How to make a custom qgraphicsitem to update

Question

I have a custom GraphicsItem with a method to toggle on/off (painting the square in green/black). But calling the method power results in no change. What I'm doing wrong?

class quadrupole(QtWidgets.QGraphicsItem):
    status_color = [QtGui.QColor('#626262'), QtGui.QColor('#32FF62')]
    def __init__(self, name):
        super(quadrupole, self).__init__()
        self.name = name
        self._on = False
        #self.setBrush(QtGui.QBrush(quadrupole.status_color[self._on]))
        self.bordersize = 2

    def power(self):
        self._on = not self._on
        self.update()
        print(f'power changed to {self._on}')
        #self.setBrush(QtGui.QBrush(quadrupole.status_color[self._on]))

    def boundingRect(self):
        return QtCore.QRectF(-25 - self.bordersize / 2, -70 - self.bordersize / 2,
                      25 + self.bordersize, 25 + self.bordersize)

    def paint(self, painter=None, style=None, widget=None):
        painter.setRenderHint(QtGui.QPainter.Antialiasing)
        #painter.setBrush(painter.brush())
        rect = QtCore.QRectF(-25, -25, 50, 50)
        painter.rotate(45)
        painter.fillRect(rect, quadrupole.status_color[self._on])
        painter.rotate(-45)

        font = painter.font()
        font.setPixelSize(14)
        painter.setFont(font)
        painter.setPen(QtGui.QColor('#FBFBFB'))
        t = QtCore.QRectF(-25, -70, 50, 20)
        painter.drawText(t, QtCore.Qt.AlignCenter, self.name)

Answer 1

Solved. The painter was constrained by a wrong boundingRect