anchor.diff:        extraDomains = mkOption {
           type = types.attrsOf (types.nullOr types.str);
           default = {};
  -        example = {
  -          "example.org" = "/srv/http/nginx";
  -          "mydomain.org" = null;
  -        };
  +        example = literalExample ''
  +          {
  +            "example.org" = "/srv/http/nginx";
  +            "mydomain.org" = null;
  +          }
  +        '';
           description = ''
             Extra domain names for which certificates are to be issued, with their
             own server roots if needed.
  
positive.code:       allowKeysForGroup = mkOption {
          type = types.bool;
          default = false;
          description = "Give read permissions to the specified group to read SSL private certificates.";
        };
  
        postRun = mkOption {
  
negative.code:         description = ''
            Attribute set of certificates to get signed and renewed.
          '';
          example = literalExample ''
            {
              "example.com" = {
                webroot = "/var/www/challenges/";
                email = "foo@example.com";
                extraDomains = { "www.example.com" = null; "foo.example.com" = "/var/www/foo/"; };
              };
              "bar.example.com" = {
                webroot = "/var/www/challenges/";
                email = "bar@example.com";
              };
            }
          '';
        };
      };
    };
  