code: def _flag_handler(self, play, handler_name, host):
          '''
          if a task has any notify elements, flag handlers for run
          at end of execution cycle for hosts that have indicated
          changes have been made
          '''
  
          found = False
          for x in play.handlers():
              if handler_name == utils.template(play.basedir, x.name, x.module_vars):
                  found = True
                  self.callbacks.on_notify(host, x.name)
                  x.notified_by.append(host)
          if not found:
              raise errors.AnsibleError("change handler (%s) is not defined" % handler_namef _flag_handler(self, play, handler_name, host):
          '''
          if a task has any notify elements, flag handlers for run
          at end of execution cycle for hosts that have indicated
          changes have been made
          '''
  
          found = False
          for x in play.handlers():
              if handler_name == utils.template(play.basedir, x.name, x.module_vars):
                  found = True
                  self.callbacks.on_notify(host, x.name)
                  x.notified_by.append(host)
          if not found:
              raise errors.AnsibleError("change handler (%s) is not defined" % handler_name)
docs: if a task has any notify elements, flag handlers for run
          at end of execution cycle for hosts that have indicated
          changes have been made