docs: def register_resources(klass, registry, resource_class):
          """ meta model subscriber on resource registration.
  
          We watch for new resource types being registered and if they
          support aws config, automatically register the jsondiff filter.
          """
          config_type = getattr(resource_class.resource_type, 'config_type', None)
          if config_type is None:
              return
          resource_class.filter_registry.register('json-diff', klass)