How to setup a proper node that uses Services form other nodes

edit

The code that made the functionality work looks like this

edit: code to initialize a simple node has been added and commentary

import sys  
import rospy
from ur_msgs.srv import SetIO

def set_io_client():
     rospy.wait_for_service('ur_driver/set_io') # look if service is online
     rospy.ini_node('relay_test') # initialize the node
     while not rospy.is_shutdown() # making sure it only runs when ros is running
     try:
           set_io = rospy.ServiceProxy('ur_driver/set_io',SetIO) # setup the proxy
           set_io(fun = 4, pin = 0, state = 24) # set the pin to 24v for the relay
           rospy.sleep(10.) # sleep for 10s
           set_io(fun = 4,pin = 0, state = 0) # set the pin to 0v for the relay
           rospy.sleep(10.)
     except: rospy.ServiceException, e: # this will do something when the function is canceld
           print "doesnt work" # debug code, so in this case it will print doesnt work when the function is interrupted or canceled


if __name__ == "__main__"
       set_io_client()
else:
       print"doesnt work right here" # only prints if __main__ condition is not met. 
       sys.exit(1) # exits system with a unnormal termination.