docs: def register_seo_admin(admin_site, metadata_class):
      """Register the backends specified in Meta.backends with the admin."""
  
      if metadata_class._meta.use_sites:
          path_admin = SitePathMetadataAdmin
          model_instance_admin = SiteModelInstanceMetadataAdmin
          model_admin = SiteModelMetadataAdmin
          view_admin = SiteViewMetadataAdmin
      else:
          path_admin = PathMetadataAdmin
          model_instance_admin = ModelInstanceMetadataAdmin
          model_admin = ModelMetadataAdmin
          view_admin = ViewMetadataAdmin
  
      def get_list_display():
          return tuple(
              name for name, obj in metadata_class._meta.elements.items()
              if obj.editable)
  
      backends = metadata_class._meta.backends
  
      if 'model' in backends:
          class ModelAdmin(model_admin):
              form = get_model_form(metadata_class)
              list_display = model_admin.list_display + get_list_display()
  
          _register_admin(admin_site, metadata_class._meta.get_model('model'),
                          ModelAdmin)
  
      if 'view' in backends:
          class ViewAdmin(view_admin):
              form = get_view_form(metadata_class)
              list_display = view_admin.list_display + get_list_display()
  
          _register_admin(admin_site, metadata_class._meta.get_model('view'),
                          ViewAdmin)
  
      if 'path' in backends:
          class PathAdmin(path_admin):
              form = get_path_form(metadata_class)
              list_display = path_admin.list_display + get_list_display()
  
          _register_admin(admin_site, metadata_class._meta.get_model('path'),
                          PathAdmin)
  
      if 'modelinstance' in backends:
          class ModelInstanceAdmin(model_instance_admin):
              form = get_modelinstance_form(metadata_class)
              list_display = (model_instance_admin.list_display +
                              get_list_display())
  
          _register_admin(admin_site,
                          metadata_class._meta.get_model('modelinstance'),
                          ModelInstanceAdmin)