'Set the size of the box (in its local coordinate system; this does not affect the transform)
Arguments can be x,y,z or size=QVector3D().'

def setSize(self, x=None, y=None, z=None, size=None):

    if (size is not None):
        x = size.x()
        y = size.y()
        z = size.z()
    self.__size = [x, y, z]
    self.update()
