anchor.diff:  	  default = null;
   	  type = types.nullOr types.path;
   	};
  -
         };
       };
     };
  
positive.code:   dbOptions = {
      type = mkOption {
        description = "Rippled database type.";
        type = types.enum ["rocksdb" "nudb" "sqlite"];
        default = "rocksdb";
      };
  
  
negative.code:     path=${db.path}
      ${optionalString (db.compression != null) ("compression=${b2i db.compression}") }
      ${optionalString (db.onlineDelete != null) ("online_delete=${toString db.onlineDelete}")}
      ${optionalString (db.advisoryDelete != null) ("advisory_delete=${b2i db.advisoryDelete}")}
      ${db.extraOpts}
    '';
  
  