def METHOD_NAME(self, event):
    rospy.loginfo("setting service mode")
    mode = self.getLightMode(random.randint(0,14))
    srv_light = rospy.ServiceProxy('/light_torso/set_light', SetLightMode)
    srv_light.call(mode)
    duration = random.uniform(0, 0.5)
    self.timer = rospy.Timer(rospy.Duration(duration), self.METHOD_NAME, True)