code: def change_svc_event_handler(self, service, event_handler_command):
          
          service.modified_attributes |= DICT_MODATTR["MODATTR_EVENT_HANDLER_COMMAND"].value
          data = {"commands": self.commands, "call": event_handler_command}
          service.change_event_handler(data)
          self.send_an_element(service.get_update_status_brok())
docs: Modify service event handler
          Format of the line that triggers function call::
  
          CHANGE_SVC_EVENT_HANDLER;<host_name>;<service_description>;<event_handler_command>
  
          :param service: service to modify event handler
          :type service: alignak.objects.service.Service
          :param event_handler_command: event handler command line
          :type event_handler_command:
          :return: None