docs: def do_metric_name_list(mc, args):
      '''List names of metrics.'''
      fields = {}
      if args.dimensions:
          fields['dimensions'] = utils.format_dimensions_query(args.dimensions)
      if args.limit:
          fields['limit'] = args.limit
      if args.offset:
          fields['offset'] = args.offset
      if args.tenant_id:
          fields['tenant_id'] = args.tenant_id
  
      try:
          metric_names = mc.metrics.list_names(**fields)
      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(metric_names))
              return
          if isinstance(metric_names, list):
              utils.print_list(metric_names, ['Name'], formatters={'Name': lambda x: x['name']})