4 from std_srvs.srv 
import Empty
 
    7 if __name__ == 
'__main__':
 
    8     rospy.init_node(
'sample_empty_service_caller')
 
    9     rospy.wait_for_service(
'~service')
 
   10     r = rospy.Rate(rospy.get_param(
'~rate', 1.0))
 
   11     while not rospy.is_shutdown():
 
   13             srv_caller = rospy.ServiceProxy(
'~service', Empty)
 
   15         except rospy.ServiceException 
as e:
 
   16             rospy.logwarn(
'Service call failed:\n{}'.format(e))
 
   20         except rospy.ROSTimeMovedBackwardsException: