def METHOD_NAME(self, value):
    if value<self.min:
        value = self.min
    if value>self.max:
        value = self.max
    self.value = value
    angle = self.value_to_angle(value)
    xy = self.value_to_xy_tuple(value, self.radius-10)
    self.arrow.attributes['transform'] = "translate(%s,%s) rotate(%s)" % (xy[0], xy[1], math.degrees(-angle))
    self.set_value_preview(value)