i wrote a subscriber python code but i did not find the mistake

#!/usr/bin/env python

import rospy

from std_msgs.msg import String

def talker() :

pub = rospy.Publisher('our_first_topic',String,queue_size=10)

rospy.init_node('publisher_node' ,anonymous=True)

rate = rospy.Rate(10)

while not rospy.is_shutdown():

first_msg = "Catch me :)"

rospy.loginfo(first_msg)

pub.publish(first_msg)

rate.sleep()

if __name__ == '__main__':

talker()