docs: def do_notification_type_list(mc, args):
      '''List notification types supported by monasca.'''
  
      try:
          notification_types = mc.notificationtypes.list()
      except (osc_exc.ClientException, k_exc.HttpError) as he:
          raise osc_exc.CommandError('%s\n%s' % (he.message, he.details))
      else:
          if args.json:
              print(utils.json_formatter(notification_types))
              return
          else:
              formatters = {'types': lambda x: x["type"]}
              # utils.print_list(notification_types['types'], ["types"], formatters=formatters)
              utils.print_list(notification_types, ["types"], formatters=formatters)