Service server doesn’t get the subscriber objects readings

edit

I wrote this class for a laser/scan subscriber:

#! /usr/bin/env python
import rospy
from sensor_msgs.msg import LaserScan
import time

class laser_sub_class(object):
    def __init__(self):
        self.subscriber = rospy.Subscriber("/kobuki/laser/scan", LaserScan, self.laser_callback)
        self.ctrl_c = False
        rospy.on_shutdown(self.shutdownhook)
        self.rate = rospy.Rate(10)


    def shutdownhook(self):
        rospy.loginfo("laser shutdownhook! stopped!")
        self.ctrl_c=True

    def laser_callback(self, msg):
        rospy.loginfo("laser_callback")
        self.range= msg.ranges

if __name__=="__main__":
    rospy.init_node("laser_scan_subscriber")
    laserScan_sub_ob = laser_sub_class()
    rospy.spin()

and, I wrote this service_server that makes an object of mentioned class: laser_sub = laser_sub_class()

#! /usr/bin/env python

import rospy
from std_srvs.srv import Trigger, TriggerResponse
from laser_scan_subscriber import laser_sub_class
import time


def serv_callback(request):
    rospy.loginfo("The Service obstacle_avoidance_service has been called")
    laser_sub = laser_sub_class()
    #time.sleep(0.3)

    r = laser_sub.range
    r_min= min(r)
    min_ind = r.index(r_min)

    response = TriggerResponse()
    response.success = True
    response.message = "straight"

    if r_min <0.4:
        response.success = False
        if min_ind<360:
            response.message = "left"
        elif min_ind>360:
            response.message = "right"
        elif min_ind==360:
            if r[0]>r[710]:
                response.message = "right"
            else:
                response.message = "left"

    return response


rospy.init_node("obst_avoid_service_server")
rospy.Service("obstacle_avoidance_service", Trigger, serv_callback)
rospy.loginfo("Service /obstacle_avoidance_service Ready")

rospy.spin()

When I call this service, I get this:

‘laser_sub_class’ object has no attribute ‘range’.

but I've declared in callback of the subscriber class that: self.range= msg.ranges

so why the object has no range attribute?