docs: def data_attrs(mapitem):
      """
      Generate the data-... attributes for a mapitem.
      """
      data_attrs = {}
  
      try:
          data_attrs['marker-detail-api-url'] = reverse('fluentcms-googlemaps-marker-detail')
      except NoReverseMatch:
          pass
  
      data_attrs.update(mapitem.get_map_options())
      return mark_safe(u''.join([
          format_html(u' data-{0}="{1}"', k.replace('_', '-'), _data_value(v))
          for k, v in data_attrs.items()
      ]))