anchor.diff:        globalConfig = mkOption {
           type = promTypes.globalConfig;
           default = {};
  -        apply = _filter;
           description = ''
             Parameters that are valid in all  configuration contexts. They
             also serve as defaults for other configuration sections
  
positive.code:       dns_sd_configs = mkOption {
          type = types.listOf promTypes.dns_sd_config;
          default = [];
          apply = x: map _filter x;
          description = ''
            List of DNS service discovery configurations.
          '';
  
negative.code:       relabel_configs = mkOption {
          type = types.listOf promTypes.relabel_config;
          default = [];
          description = ''
            List of relabel configurations.
          '';
  